Known Issues and bugs

Key: current bugs in red     fixed bugs in green
Tip: Try the latest E2B Beta version.

Known BIOS issues

  1. 137GB limit - many BIOSes have a bug in their USB driver code - they cannot access any sectors past 137GB (128GiB) on a USB drive. This bug is very common. Once the linux or Windows OS has booted, there is no problem because linux\Windows does not use the BIOS. E2B uses grub4dos however, and grub4dos, MS-DOS, FreeDOS, Windows 3, Win95, Win98 all use the BIOS. You may also have problems booting WindowsToGo or WinPE flat-file installs on these systems (e.g. if the \bootmgr file is past 137GB on the USB disk).
  2. USB\Internal drive confusion - If a system BIOS has a pop-up BIOS Boot Selection (BBS) Menu (e.g. F8 or F12 or ESC), always use that to boot from the USB drive. If possible avoid setting the BIOS boot order with the USB drive as the first boot device. This can cause problems when repairing or installing OS's on some systems.
  3. No CSM\MBR-boot choice - If you have a UEFI system, some of them do not display an MBR\CSM boot option to boot to the E2B\CSM menu. This is usually because there is \EFI boot files present on the E2B drive. This situation can occur when you use .imgPTN files and switch to the CSM menu. This is a BIOS/UEFI firmware bug. Solution: Look for a 'Windows 8' boot option in the BIOS setup and disable it. Try to update the firmware/BIOS. Otherwise, if you want to MBR-boot, you will have to use another system or an emulator/VM or run the \e2b\Restore_E2B.cmd or \e2b\SWITCH_E2B.exe file to return the E2B drive to it's original state.
    Known systems with this 'bad BIOS' behaviour are, Fujitsu LifeBook AH532, some Samsung and Acer systems - these will only offer the UEFI boot option. To boot in CSM\MBR\Legacy mode to grub4dos, you will need to use QEMU or a VM or a different system.
  4. GIGABYTE GA-73PVM-S2H (version F7/F8/F9E BIOS) - immediate hang on boot, before any grub4dos messages, etc. - can fix by  replacing grub4dos MBR on USB with standard MBR boot code (use RMPrepUSB - Ctrl-B to replace MBR). .imgPTN files cannot be used unless grub4dos MBR is installed. Try later or older BIOS (many people have reported issues with this BIOS!). GA-73PVM-S2H BIOSes later than version F6 do not boot from grub4dos MBR boot code (hang immediately) - use the older version F6 BIOS.
  5. Some BIOSes cannot UEFI-boot from a partition which has been formatted as FAT32 and is over 64GB in size due to the non-standard cluster size used by >32GB FAT32 volumes. This issue should not affect E2B however, as you are UEFI-booting from smaller .imgPTN partitions. Although Rufus and RMPrepUSB can create FAT32 partitions larger than 32GB, some UEFI implementations do not seem to like the 'non-standard' format. Note: reference here.
  6. Some BIOSes MBR-boot a USB flash drive as a Floppy disk or a ZIP drive instead of as a USB-HDD. Some BIOSes do not support LBA addressing on USB devices. If you have already tried a BIOS update, then I recommend FlashBoot + E2B as a way to get around this issue. Ensure that the USB drive has two or more Primary partitions.
  7. Some BIOSes will not provide a UEFI boot option even if a valid FAT32 first partition is present containing valid EFI boot files. In this case, check for any other partitions on the same USB drive (e.g. linux type 0x83 partitions, etc.) and delete them if they are not required.  Ensure that all partitions are in ascending order (the start address of the Ptn1 < start of Ptn2 < start of Ptn3 < start of Ptn4). Asus Z87 firmware has this bug.
  8. Some BIOSes only assign a BIOS device number on a cold boot (from power-on). If you reboot using 'restart' or Ctrl-Alt-Del, the BIOS may not be aware of any changes you may have made to the USB drive (e.g. it may still try to boot it as a floppy disk instead of a hard disk). If you have problems booting from USB drives on a particular system, always cold boot (switch off power - switch on power), so that the BIOS re-evaluates the USB drive during Power On Self Test.
See also 'Slow and buggy BIOSes' page.

grub4dos bugs affecting E2B      

All current grub4dos issues can be viewed here. Note that many versions of grub4dos are buggy - the latest versions may have bugs! Only use the version of grub4dos (\grldr) that is included with E2B!
1. copying to a fragmented NTFS file fails (only 8KB copied) - Fixed in grub4dos 25-08-2104
2. splashimage - command fails if greater than about 64 characters  - Fixed in grub4dos 25-08-2104 (127 max length)
3. partnew command fails with 'not contiguous' if exFAT file > 4GB  - Fixed in grub4dos 25-08-2104
4. cat --length=0  returns file length but only in range +/- 2GB (worked around in E2B) - Partially fixed in grub4dos 25-08-2014 (now returns -1 = 3.9999GB if over 4GB)
5. grub4dos 0.4.6a has problems with large exFAT drives due to warning/error messages - Fixed in 2014-01-17 and later versions.
6. grub4dos 0.4.6a has problems with some ISO files (e.g. Windows Joilet ISOs) - seems to be fixed now? 0.4.5c does not support Joliet ISOs.  (fixed in 2015-06-05 0.4.6a)
7. grub4dos 0.4.6a + exFAT - if boot directly to grldr 0.4.6a then cannot map ISO files - strangely, OK if boot 0.4.5c first and then chainload /grldr046.
8. Cannot write to small files (<800 bytes) on an NTFS volume (all versions - long-standing issue). Fixed in 0.4.6a 2015-05-08 version of grldr.
9. grub4dos 0.4.6a partnew does not display an error if file is non-contiguous (2015-02-09 and before)
10. grub4dos 0.4.6a 2015-05-18 - various crashing/no iso boot issues if ISO is UDF format or multiple initrd files loaded. Workaround: use grub4dos 0.4.5c. Known issue with Parted Magic 2015_05_04 ISO. See Error #64 and #65 at for details. (fixed in 2015-06-05 0.4.6a)
11. E2B hangs or goes to command prompt after enumerating files and 'Wiping /Unattend.xml and /AutoUnattend.xml files... 1 0 ' message - (grub4dos 0.4.6a 2015-08-25 bug with GPT partitions)  If you are using a Removable-disk E2B USB drive, add set NOHELPER=1 to your \_ISO\MyE2B.cfg file - if using a Fixed-Disk for E2B,  replace the \grldr file (0.4.6a) with the \_ISO\e2b\grub\grldr_045 file (keep name as \grldr) to use version 0.4.5c instead of 0.4.6a. Bug is in 0.4.6a and is due to a problem with GPT partitions on other drives in the system. Should be fixed in grub4dos 0.4.6a August 2016 version (let me know if not!).
12. On some systems, E2B reports a 'E2B.cfg is missing' error, but it works OK on other systems or in VBox and QEMU. Using grub4dos 0.4.5c may fix this. A 'E2B.cfg is MISSING' error can occur if grub4dos 0.4.6a detects a certain kind of (ext?) partition on a system hard disk (e.g. empty ext swap partition???). This typically occurs immediately after installing a linux OS to the system disk and then rebooting to E2B (or trying to!). If you replace the \grldr file with the \_ISO\e2b\grub\grub_045 file (keep the name as \grldr) then it will fix the issue OR try booting from the system disk and using the swap partition under linux or formatting any unformatted/unused/empty partitions in the system. The reason for this grub4dos 0.4.6a bug is unknown because it is very difficult to reproduce! If you find away to reproduce this issue or if you are still seeing this error on some systems, please Contact Me. Fixed in E2B v1.82 (grub4dos 0.4.6a August 2016)
13. On some systems, E2B just doesn't work properly or reports disk errors, etc. This seems to be caused by the system containing a hard disk partition which grub4dos does not 'like'. This is usually fixed by using grub4dos 0.4.5c. Similar issue (same?) to 11 and 12 above. Fixed in v1.82 by new \grldr grub4dos 0.4.6a August 2016 version.
14. Grub4dos 'fat' utility fails to copy some file from an ISO unless full path is used with device name. Fixed in copyff.g4b in E2B by specifying full path name.
15. Some XP Install ISOs cause E2B to hang or reset just before booting to ISO. Fixed in August 2016 (E2B v1.82+).

Known E2B bugs

1. Just running an XP install ISO and then using F3 to reboot (without formatting or installing) would cause the OS on the internal hard disk to BSOD. This was fixed in E2B v1.64.
2. E2B 1.67 - some .txt files caused .iso not to appear in Menu. Fixed in 1.68+
3. E2B v1.80 and some previous versions reported an error in a Windows command form when booting to a .isoPE or .isoPE01 file and the ISO was not loaded as a virtual drive. This was fixed in E2B v1.81.
4. If SWITCH_E2B.exe was used to switch in a newly made .imgPTN file, and it used syslinux, then some of the CSM menu boot options did not work unless you selected the .imgPTN file using the E2B menu first. This was fixed with a newer version of SWITCH_E2B.exe (in E2B v1.81+).
5. .VHD, .VHDX and .WIM filenames should not contain spaces. This is now checked for in E2B v1.81.
6. When installing Windows 7/8/10 from an ISO, Setup will not allow you to install Windows to the internal hard disk. Typically you get an error message 'We couldn't create a new partition or locate an existing partition'. This issue may be fixed by E2B v1.82. You may only see this problem if your BIOS assigns a different drive (e.g. WINHELPER USB drive or other USB drive or SD card) as drive 1. Normally, a BIOS should assign the E2B drive as drive 0 and the internal drive as drive 1 - E2B then swaps drive 0 with drive 1 so that Windows Setup thinks that the internal hard disk was the boot drive. However, some BIOSes assign other drives as drive 1 (e.g. drive 0 = E2B, drive 1 = WINHELPER flash drive or SD card, drive 2 = internal hard disk. If you still have this issue using E2B v1.82 or later, remove all drives, SD cards, USB drives, etc. so that only the E2B drive and the target internal hard disk are present - then press F8 or F12 to get the pop-up boot menu - then connect the WINHELPER USB flash drive if you are using an E2B HDD drive - and continue to boot from the E2B drive.

Known 'bad' USB drives

Always check any new USB drive using RMPrepUSB's Quick Size Test button or FakeFlashTest!
It only takes a few minutes and could save you hours of frustration!
The following drives or drives+BIOS seems to have problems (at least for some users).
  1. SanDisk USB 3.0  Cruzer UltraFit - seems to have problems when USB interface is reset (e.g. 'linux initramfs not found', etc.). May also be 'Fixed-Disk' type.
  2. Mushkin USB drives
  3. HP InSyde BIOS+Danelec/MSI USB flash drives
  4. Emtec 64gb USB 3.0 color mix flash drives.
  5. Some PNY 16Gb Retract Flash drives have buggy firmware - see this or this for a possible fix.
  6. Silicon Power 32Gb B30 (missing files in root, etc., e.g. \AutoUnattend.xml, no Blue console window on Windows ISO boots)
  7. Lexar P20 USB 3.0 Flash drive - very slow when copying files onto it - copying lots of small files can take ages (e.g. Make E2B+DPMS - 20 minutes). This is due to a 'feature' of the controller used in this drive (and Kingston HyperX??). Large files copy quickly, lots of small files are REALLY SLOWWWWWW... Under grub4dos it is also half the speed of the SanDisk Extreme! Avoid this type of drive for E2B.
I recommend the Sandisk Ex treme Cruzer USB 3.0 for great speed at a reasonable price.

Other issues

  1. E2B does not work when booted with Plop! which uses a read-only USB 2.0 driver. You can try the grub4dos USB 2.0 driver from the Utilities menu which is rd/wr, but this recognises a limited range of USB controllers and does not always work.
    You can also try booting from a grub4dos+Plop! CD - see this blog post for details.
  2. Acronis True Image2019 installs Acronis Active Protection which can block Switch_E2B.exe and prevent making an E2B SUB drive. May also cause BSOD with WinContig or block RMPrepUSB too.
  3. Some AV applications may falsely detect a virus or Potentially Unwanted Progaram\Application (PUP\PUA) when using Make_E2B.exe or the E2B .cmd scripts. You may need to temporarily disable it or add it to the applications whitelist.

    Other troublesome apps:
  4. ASUS USB 3.0 Boost Storage Driver
  5. Avira Antivirus
  6. Bit Defender Client Security
  7. Defraggler
  8. Explorer++
  9. Genie Timeline Backup Pro
  10. Panda USB vaccine
  11. Paragon ExtFS for Windows / Paragon HFS+ for Windows
  12. RealPlayer Cloud
  13. Trend Micro OfficeScan and some other versions of Trend Anti Virus.
  14. USB Drive Letter Manager
  15. Comodo AV
  16. CyberReason AntiRansomware

Recommended for Easy2Boot (fastest flash drive!)
SanDisk Extreme SDCZ880-128G-G46

Fastest USB 3!
See Blog post


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