Passing this along as a heads up… now mind you I have installed this patch on several machines with zero issues. And point number two – remember AN
[See the full post at: EFI Partition issues?]
Susan Bradley Patch Lady/Prudent patcher
![]() |
Patch reliability is unclear. Unless you have an immediate, pressing need to install a specific patch, don't do it. |
SIGN IN | Not a member? | REGISTER | PLUS MEMBERSHIP |
Home » Forums » Newsletter and Homepage topics » EFI Partition issues?
Passing this along as a heads up… now mind you I have installed this patch on several machines with zero issues. And point number two – remember AN
[See the full post at: EFI Partition issues?]
Susan Bradley Patch Lady/Prudent patcher
Macrium Reflect’s Rescue Media should be able to solve this problem. A couple of years ago I bricked a Win7 installation by configuring Windows to allow the installation of unsigned drivers. Upon reboot, I found that Win7 EFI boot was bricked. I tried everything under the sun to fix it.
Then I had the bright idea to boot with Reflect’s Rescue Media. I then chose to have Reflect repair any detected boot issues. Reflect worked like magic by fixing the problem.
GoneToPlaid is correct. Definitely have a Macrium Reflect Rescue Media (and access to its instructions) handy before you do anything that might affect your boot loading. And I’ve only ever had the Free version of Macrium.
I moved an entire PC from smaller HDD to larger HDD twice (once with I-don’t-remember and once with Macrium Reflect), both times the booting was borked, and both times the Macrium Rescue Media fixed it very quickly.
Cheers.
I wonder how often this person restarts each month.
If you only ever restart when Patch Tuesday updates demand it, and that reboot fails, it seems too easy to assume that a windows update has caused the boot failure, rather than anything else during the preceding weeks.
It doesn’t take malware. Sometimes an EFI Partition for some reason goes haywire, especially in a dual-boot. I’ve been dual-booting for many years, and find this can happen for (at the time) unknown reasons. Never from an errant OS or software update. But can happen after a Feature Upgrade or an in-place Linux Upgrade.
Linux also has kernel updates. These can have unpredictable side-effects.
-- rc primak
I wonder how often this person restarts each month.
My NAS only reboots when an update requires it, runs 24/7 otherwise, and I’ve had no issues with EFI there or on my dual boot daily driver.
I have a full drive image of my NAS OS, and I could restore the EFI partition in a couple minutes if it ever became necessary.
When you have two EFI partitions that typically means you dual boot and I always consider a dual booting machine an advanced setup that you should consider a bit more carefully and ensure it’s backed up.
Dual booting only requires a bootloader and a menu, not two EFI partitions. I have only one EFI partition (and I keep an up-to-date drive image of it) and dual boot Windows. Linux can boot from Grub with a menu option to dual boot Windows from EFI.
Dual booting only requires a bootloader and a menu, not two EFI partitions
I suppose the user has two drives with two OSs and two EFI partitions.
I suppose the user has two drives with two OSs and two EFI partitions.
Unnecessary. I’ve got six drives, dual boot (plus Recovery Environment), only one EFI partition is necessary regardless of the number of OS’s. The EFI partition contains the BCD store, the boot menu (which in Windows is bootmgr), which can have several items with the capability of booting several OS’s. Mine has three menu items:
Windows Boot Manager
——————–
identifier {bootmgr}
device partition=\Device\HarddiskVolume17
path \EFI\Microsoft\Boot\bootmgfw.efi
description Windows Boot Manager
locale en-US
inherit {globalsettings}
default {current}
resumeobject {f29ecede-e33b-11eb-a19b-00224db0e3fa}
displayorder {current}
{cc210e8f-d26f-11e9-8049-00224db0e3fa}
{06b464b1-8ecc-11e9-931d-ed7d6d74d09b}
toolsdisplayorder {memdiag}
timeout 10
displaybootmenu Yes
Windows Boot Loader
——————-
identifier {current}
device partition=C:
path \WINDOWS\system32\winload.efi
description Win10 ProA
locale en-US
inherit {bootloadersettings}
recoverysequence {c25eed68-e367-11eb-a19c-00224db0e3fa}
displaymessageoverride Recovery
recoveryenabled Yes
isolatedcontext Yes
allowedinmemorysettings 0x15000075
osdevice partition=C:
systemroot \WINDOWS
resumeobject {f29ecede-e33b-11eb-a19b-00224db0e3fa}
nx OptIn
bootmenupolicy Standard
Windows Boot Loader
——————-
identifier {cc210e8f-d26f-11e9-8049-00224db0e3fa}
device partition=B:
path \WINDOWS\system32\winload.efi
description Win10 ProB
locale en-US
inherit {bootloadersettings}
recoverysequence {7abbfa11-e35c-11eb-81d4-00224db0e3fa}
displaymessageoverride CommandPrompt
recoveryenabled Yes
isolatedcontext Yes
allowedinmemorysettings 0x15000075
osdevice partition=B:
systemroot \WINDOWS
resumeobject {614d2df5-de72-11eb-81ce-806e6f6e6963}
nx OptIn
bootmenupolicy Standard
Windows Boot Loader
——————-
identifier {06b464b1-8ecc-11e9-931d-ed7d6d74d09b}
device ramdisk=[\Device\HarddiskVolume6]\Recovery\WindowsRE\Winre.wim,{06b464b2-8ecc-11e9-931d-ed7d6d74d09b}
path \windows\system32\winload.efi
description Windows RE
locale en-US
inherit {bootloadersettings}
displaymessage Recovery
osdevice ramdisk=[\Device\HarddiskVolume6]\Recovery\WindowsRE\Winre.wim,{06b464b2-8ecc-11e9-931d-ed7d6d74d09b}
systemroot \windows
nx OptIn
bootmenupolicy Standard
winpe Yes
Essentially the GRUB Boot Menu list has the same multiple boot options, and uses only one EFI partition.
-- rc primak
As you said, you don’t need more than one EFI partition.
On my desktop PC, I have three SSDs and one HDD, and the OSes include KDE Neon, Kubuntu, Fedora, and Windows 8.1, in a quad boot setup. All of the drives are GPT, but only the first one has an EFI System Partition (ESP). The ESP contains the bootloaders for each of the Linux versions and for Windows.
The Linux root partitions are all on the first SSD, while the second is for Linux /home. The third contains Windows 8.1 (OS itself and program files), while the HDD (encrypted by LUKS) contains all of the data files (pictures, videos, documents, stuff like that), as well as the browser and email client profiles and such.
I have had similar (but with fewer physical drives) setup on my other PCs, and each has had only one ESP. The only legacy/BIOS/MBR boot systems I have are those that lack UEFI (the newest being from 2008). The desktop itself is from about 2012, when UEFI was still young, but it works well. No secure boot, though.
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
Had this problem with one laptop in the JuNe round, never experienced anything like that before. Solved the problem by restoring an image made before updating. No time (and energy anymore) to figure out what went wrong this time…
Very basic system, single EFI, single OS with basically only Office, Firefox, Thunderbird etc installed. That’s also why I don’t bother even anymore to waste my precious time to figure out Windows troubles anymore. Restoring an image takes about 10…15 minutes, much more efficient. In 99.9% the problem is solved then, this time also.
When you have two EFI partitions that typically means you dual boot and I always consider a dual booting machine an advanced setup that you should consider a bit more carefully and ensure it’s backed up.
Dual booting only requires a bootloader and a menu, not two EFI partitions. I have only one EFI partition (and I keep an up-to-date drive image of it) and dual boot Windows. Linux can boot from Grub with a menu option to dual boot Windows from EFI.
Although multiple EFI System Partitions (ESPs) are not required for multi-booting, neither is such an arrangement impossible. The “hunch” of the poster under discussion in this case may, in fact, be within the realm of contributing factors, but insufficient information is provided to be certain. Much depends on the mobo OEM’s UEFI implementation and on its Firmware Boot Manager handing of the boot configuration data (BCD) {fwbootmgr} section.
The other contributing factor is the boot loader/manager used by each operating system in a multi-boot setup. Grub is certainly capable of handling ESPs on more than a single drive. The Windows boot loader, on the other hand, isn’t.
The Windows boot loader, on the other hand, isn’t.
For the Windows bootloader, it is completely unnecessary. In Linux, one must use Grub as a bootloader, and the Windows EFI partition path can be in the Grub bootloader.
One can boot multiple Windows versions using a single EFI partition. The relevant information is in the BCD Store and handled by bootmgr to point to the correct path to load the selected version of Windows.
So even dual booting Linux, one needs only Grub containing the path to a single EFI partition to be able to boot Linux and multiple versions/configurations of Windows. There is absolutely no need for more than one EFI partition.
In Linux, one must use Grub as a bootloader, and the Windows EFI partition path can be in the Grub bootloader.
You don’t need to use GRUB. There are other bootloaders, including the kernel itself. I set it up to use the kernel itself to boot just for giggles on my XPS, but GRUB is just too convenient for me to want to keep it that way for long. I like being able to select the kernel and edit the boot parameters on the fly (for a single boot, for testing purposes).
When you install or update GRUB, it will (on most distros) use os-prober or equivalent to find other OSes on the system, and GRUB will automatically add each of them to its menu to be presented at boot time. It can chainload Windows from a different ESP than the one Linux/GRUB booted from, and if I am not mistaken, I think it can even chainload a MBR Windows setup (though don’t quote me on that).
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
Much depends on the mobo OEM’s UEFI implementation and on its Firmware Boot Manager handing of the boot configuration data (BCD) {fwbootmgr} section.
Not necessarily true. The motherboard firmware EFI has to be selected by entering UEFI settings. Multiple scripting opportunities are available in firmware, but not needed in any normal OS installation(s). It is not normally used when booting an OS. Linux does not need/use EFI.
When installing a version of Windows in a UEFI system, the installation routine will first look for an EFI partition. If one exists, the new installation will add its own entries to that single EFI partition.
Linux does not need/use EFI.
I am not sure what you mean by that. Linux does not need to perform an EFI boot, since there are no restrictions on where a legacy/MBR/BIOS boot can be used, but it is certainly advisable to use EFI, for all of the same reasons that apply to Windows (where it gives you the choice). I (sometimes) use Secure Boot on my Linux laptops, and secure boot requires UEFI.
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
This thread:
https://news.ycombinator.com/item?id=16261237
and several other similar threads, lead me to believe that more than one EFI partition on a single device is not a normal or acceptable condition.
While the exact causes are not discovered in any of these threads, it seems quite obvious that more than one EFI partition is not normal, and is not desirable.
It is also not something that any Windows update or upgrade should be causing.
That is, unless the original questioner mistook System Reserved partitions for EFI partitions, which did happen in some of the threads I’ve read.
These threads also definitively say that extra EFI partitions are NOT the result of dual-booting. Nor are they the result of having Linux on the device.
-- rc primak
That link was about multiple ESPs on the same drive, not on different drives in the same PC. Multiple ESPs on the same drive would not occur outside of some kind of bug or glitch by any normal OS installation, but it could happen quite easily (and the Linux installer provides this as an option) if you mean having an ESP on more than one physical disk.
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
Hi to everyone. My first post here.
I wanted to mention I updated my windows 10 20h2 tonight to KB5004237. Everything seemed ok after reboot. I did some maintenance, ran “disk cleanup”, then did what I normally do after an update, I used an elevated command prompt to schedule a “chkdsk” for drive C and my other partition D.
It rebooted fine, ran through the chkdsk as it normally does, then rebooted and spent the next about half hour with a screen saying “Attempting repairs”. After that ran, it rebooted finally and I saw in the notification box it stated it had a “Start up failure” and removed some recently installed updates.
I have no idea what happened but thought I would let everyone know. My disk is healthy, no issues, but after doing my routine maintenance and after running a scheduled chkdsk, it had a start up failure. never had that happen before. It fixed itself by removing the KB5004237 latest cumulative update. So, apparently, something went wrong with either the latest update, OR during the chkdsk.
I went ahead and restored to a previous backup I had and computer is fine. I didn’t even bother checking the log files, I just restarted and restored a drive image from July 11 to make sure I got rid of any other potential issues. Everything is fine now. My advice after wasting 1.5 hours is to wait on KB5004237. Just sharing my experience…first time this has ever happened.
I am not mistaken, I think it can even chainload a MBR Windows setup (though don’t quote me on that).
It is certainly possible to include multiple Grub2 modules (i386-pc, i386-efi, x86_64-efi) so that it is capable of handling whichever configuration is employed for any given system startup. Can be handy for booting up portable “rescue” utilities on a USB thumb drive, for example, and that can even be done from Windows. (Details here if interested.)
These threads also definitively say that extra EFI partitions are NOT the result of dual-booting. Nor are they the result of having Linux on the device.
Generally true that multiple ESPs are neither “normal” nor desirable. Adam Williamson’s article (here) on the subject, while somewhat dated, provides a good explanation of why not. On the other hand, such arrangements are not unheard of and can even be useful in some circumstances such as the creation of independently bootable portables. In fact, Grub boot loader placement anomalies can result from the behavioral “quirks” of some Linux distro installers (Ubiquity is notorious) that may sometimes override specific user instructions.
For the Windows bootloader, it is completely unnecessary.
Yes, I stipulated quite clearly that multiple ESPs are not required for multibooting. Not for the Windows boot loader and not for the Grub boot loader either. A single ESP can allow either to boot multiple OSes.
As I also said, however, and as the poster in question speculates, situations involving multiple ESPs can and do arise for various reasons. In that case Grub can handle it, but the Windows boot loader/manager can’t.
anonymous wrote: Much depends on the mobo OEM’s UEFI implementation and on its Firmware Boot Manager handing of the boot configuration data (BCD) {fwbootmgr} section. — Not necessarily true.
Sorry, but I’m not really sure what you are saying is not necessarily true. OEM implementations of the UEFI protocol and their impacts on multi-booting setups vary widely. In fact, in some recent cases, they are increasingly making anything other than booting to Windows nearly impossible. In which case, if the default /EFI/boot/bootx64.efi entry gets messed up somehow, it’s an “up the creek without a paddle” situation for many users who venture into multi-booting without any very clear understanding of their own OEM’s UEFI implementation.
Creating a user ID here doesn’t mean you lose your anonymity. Just don’t use your real name for a user ID!
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
Susan: “t monthly patches don’t move a EFI partition” — a word of history on that point, the Win 10 1709 version update did cause partition issues for a number of people, preventing Windows boot up (as on several Win 10 machines here). So to be a bit more accurate, there have been some past issues with Win 10 handling of existing partition layouts.
As I get old the patch issues blur and I forget some of the issues. Microsoft withdraws AMD driver that causes INACCESSIBLE_BOOT_DEVICE error in Windows 10 (betanews.com) You talking about that? They do react when partitions aren’t big enough, but typically patches don’t move existing partitions. That’s a “under the OS” kind of thing that patches don’t touch.
Susan Bradley Patch Lady/Prudent patcher
Are you perhaps referring to the way in which major Windows updates install newer (larger) versions of its recovery image (WinRE.wim) file. In that case, if the existing dedicated recovery partition is not large enough to accommodate the newer image, it is handled according to the procedure described here under the heading Updating the On-disk Windows Recovery Environment.
Note that, in some circumstances, this may result in creating a new WinRE partition and “orphaning” the old one. But, as you say, I’m not aware of any other similar Windows patching process that affects partitioning as such.
Also I use the term “patches” for these monthly updates. They shouldn’t touch a recovery partition. Feature updates and service packs do blow up stuff. Monthly updates in theory shouldn’t. Now I do see that patches – or rather rebooting do expose underlying issues.
Susan Bradley Patch Lady/Prudent patcher
In the old days, I ran an NT update that trashed my hard drive rendering it unbootable upon reboot, a well known issue for that Windows NT 3.x update. I spent painful hours on the phone with support together editing my partition table byte by byte. The edits eventually worked for my unbacked-up multi-boot Windows only test PC.
So even backing up a carefully crafted test machine can be worthwhile before running Windows Update. I also like to start off with a fresh reboot before starting a Windows Update, if any hint of these issues, for problem isolation.
Windows 10 22H2 desktops & laptops on Dell, HP, ASUS; No servers, no domain.
Creating a user ID here doesn’t mean you lose your anonymity. Just don’t use your real name for a user ID!
So , Askwoody.com is GDPR and/or BDSG compliant right now?
No idea. I wasn’t talking about regulatory compliance. I was talking about how having a user account on AskWoody.com doesn’t reveal anything more about you than posting anonymously.
Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)
Windows/Linux dual boot configurations and the Linux Live USB Image on the flash stick is always accompanying the laptop in case things get messed up there. And I had that happen after a DDU uninstaller session booted into Windows 7 on an Win 7/Linux Mint dual boot laptop but I just booted the laptop with the Linux Live image on the USB Stick and from that session mounted my proper filesystem/directory and upgraded GRUB and that fixed that so the laptop could boot Mint again!
But full system Image Backups are always done on a regular basis especially if any dangerous things are attempted!
Generally speaking, any new OS or major update that is installed to a UFI-GPT multi-boot setup will replace the default /EFI/boot/bootx64.efi entry with a copy of its own boot loader. For example, a copy of the bootmgfw.efi loader for Windows or a copy of the grubx64.efi (or shimx64.efi) loader for Linux may overwrite the /EFI/boot/bootx64.efi file that is most often set as the default boot entry in UEFI firmware configurations.
Correcting that problem can be as straightforward as simply copying the desired boot loader back to the default /EFI/boot/bootx64.efi EFI System Partition (ESP) again. Or else modifying the UEFI firmware setup so that its specifies the desired OS boot loader as the default boot option. The biggest difficulty faced by many users is knowing exactly what problem has occurred and how to get to it for correction. And, of course, backup image restoration is almost always a “surefire” solution provided that the ESP was included in the image.
So does any of this create a new EFI or ESP Partition? In other words, is this relevant to the issue originally posted?
My favorite Windows backup program, Macrium Reflect, allows an option to back all partitions needed to boot Windows, which should include the ESP or EFI Partition and the Reserved Partition(s).
But could such backup software get fooled if there are multiple EFI Partitions present on one disk? Maybe…
-- rc primak
Never having dealt with multiple ESPs on the same physical drive myself, I can’t really answer your question about the possibility of its fooling Macrium Reflect. When I was using reflect (now switched to Terabyte with native Linux support) I always told it to back up the selected drive(s) entirely so that it wasn’t really an issue in any case. At least not unless and until one needed to restore one or more individual partitions.
As for multiple ESPs on multiple drives, I have created that arrangement quite deliberately for some portable drive setups. And I’ve also encountered situations where the OS installer insists on populating an ESP other than the one it was told to use. Ubiquity, for example relies entirely on whatever efi-boot flag it happens to find first, even despite any specific user instructions to the contrary. Unfortunately, the information provided by the poster in question is insufficient to sat with any certainty whether multiple ESPs are actually involved in that situation, let alone whether an OS update was actually all or part of the underlying issue. So relevance is an open question at best.
___
unique ‘anonyous’ signature 🙂
What tool should I use to determine absolutely positively what each partition on my three hard disks is?
My Dell Optiplex 7010 dual-boots Win 7 Pro 64-bit and Win 10 Pro 64-bit (currently version 21H2). I must have been lucky when I first set that up maybe eight years ago (and what is now the 10 originally started as 8 and 8.1). I’m pretty sure I’m using UEFI exclusively without Legacy and NOT Secure Boot, but I have no idea which EFI or ESP partitions I have.
Thanks.
Paul T – Your good suggestion shows that I have two EFI partitions in my dual-booting PC. (I am dual-booting Win 7 Pro 64-bit and Win 10 Pro 64-bit v 20H2. I added the dual-boot years ago, and what is now the Win 10 originally started as Win 8.)
The first one is at the very beginning of my C:/ drive and has many more subfolders, some of which have been very recently updated. The C:/ drive holds both my Win 10 and my Win 7 OSes.
The second EFI partition is on my G:/ drive but not at the beginning. (The G:/ drive is what I I try to use for data files only.) This EFI partition has fewer folders than the first and none of those folders show a date past 2015.
I shall leave them both alone, as the dual-booting has never been a problem, and I have been able to do the Win 10 version upgrades from time to time without a problem.
FWIW, I also have NeoSmart’s iReboot function running at all times, which has been hugely helpful. It comes with NeoSmart’s EasyBCD. Maybe these two apps have kept me “regular” all these years.
Also, on at least one occasion when I moved my system from a single smaller HDD to the current larger three HDDs using Macrium Reflect Free, I had a boot problem and used the Macrium Reflect Rescue Media to fix that (very quckly). Maybe that also helped keep things going.
Thanks.
Donations from Plus members keep this site going. You can identify the people who support AskWoody by the Plus badge on their avatars.
AskWoody Plus members not only get access to all of the contents of this site -- including Susan Bradley's frequently updated Patch Watch listing -- they also receive weekly AskWoody Plus Newsletters (formerly Windows Secrets Newsletter) and AskWoody Plus Alerts, emails when there are important breaking developments.
Welcome to our unique respite from the madness.
It's easy to post questions about Windows 11, Windows 10, Win8.1, Win7, Surface, Office, or browse through our Forums. Post anonymously or register for greater privileges. Keep it civil, please: Decorous Lounge rules strictly enforced. Questions? Contact Customer Support.
Want to Advertise in the free newsletter? How about a gift subscription in honor of a birthday? Send an email to sb@askwoody.com to ask how.
Mastodon profile for DefConPatch
Mastodon profile for AskWoody
Home • About • FAQ • Posts & Privacy • Forums • My Account
Register • Free Newsletter • Plus Membership • Gift Certificates • MS-DEFCON Alerts
Copyright ©2004-2025 by AskWoody Tech LLC. All Rights Reserved.