I keep getting this error code when backing up, and the back up fails.
I haven't tried backing up in over a year. The same volume is
connected. I tried "refreshing" the list of storage devices. I deleted
a prior back up, yet it's still the same error. Screen shot below. Any
suggestions would be appreciated!

https://postimg.cc/mPKbvJsK

Michael Trew <michael.trew@att.net> wrote:

> I keep getting this error code when backing up, and the back up fails.
> I haven't tried backing up in over a year. The same volume is
> connected. I tried "refreshing" the list of storage devices. I deleted
> a prior back up, yet it's still the same error. Screen shot below. Any
> suggestions would be appreciated!
>
> https://postimg.cc/mPKbvJsK

I've never used the Backup program bundled in Windows. I prefer more
robust 3rd-party backup programs.

Okay, I'll ask the obvious. In the screenshot of the error message, it
says several possibilities for the error.

- What is the name of the destination file for the backup? Is there a
file already by that name?

- What is the name of the destination folder for where to store the
backup file? Does that older exist?

- To what drive (by letter) does the backup get saved? When you look in
Windows Explorer, is there a drive mounted by that letter? If so, can
you probe around inside that external USB HDD to look at files? If
the drive is removable media, is the external drive plugged in when
the backup is ran? Can you write a test file to that drive (F:)?
According to the error message, the destination drive
is "Toshiba Canvio Hard Drive" with drive letter F:. From the
description, doesn't seem a USB flash drive, but instead a USB HDD.
Is it plugged in? If so, can you see it in Windows Explorer as
drive F:? Does it spin up when plugged in to a USB port? To what
type of USB port are you plugging in that external HDD? USB1, USB2,
USB3, and what type of port connections (USB-A, USB-C)?

On 10/29/2021 11:19 PM, Michael Trew wrote:
> I keep getting this error code when backing up, and the back up fails. I haven't tried backing up in over a year.  The same volume is connected.  I tried "refreshing" the list of storage devices.  I deleted a prior back up, yet it's still the same error.  Screen shot below.  Any suggestions would be appreciated!
>
> https://postimg.cc/mPKbvJsK

Reset with this.

( https://www.tenforums.com/tutorials/75528-reset-windows-backup-default-windows-10-a.html )

https://www.tenforums.com/attachments/tutorials/287795d1594588274-reset-windows-backup-default-windows-10-a-reset_windows_backup.bat

You can examine that file, using "Edit" with Notepad, to see what
it is doing. You can even manually use Regedit and Scheduled Tasks and
examine the information it is modifying.

Reg Delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsBackup /F

Reg Add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsBackup

schtasks /delete /tn "Microsoft\Windows\WindowsBackup\AutomaticBackup" /F

schtasks /delete /tn "Microsoft\Windows\WindowsBackup\Windows Backup Monitor" /F

Open a Command Prompt as Administrator.

cd /d C:\users\UserName\Downloads
reset_windows_backup.bat

There should be four "OK" style messages as output.

Clean off the backup drive, if you want. During my tests,
I reformatted my S: drive that I was using for backups.

The contents of the HKLM entry, don't really spell out a lot.
This suggests that the wbengine is evaluating the AllCritical indicator
to make a System Image, each time it is called. On mine (UEFI/GPT) it
captured the ESP (which has boot materials) as well as C: , as the
System Image two partitions to capture.

The backup drive is identified by drive letter, as well as by what
could be a Mountvol value. If you changed backup drives, maybe
that is what is causing the error. But I can't be sure about that.

LastBackupDrive S:
LastBackupLocation \\?\Volume{5c189dc1-53e7-4b9e-951e-71d86c2bfd9c} <=== "mountvol" command gives these

In any case, the HKLM doesn't contain a lot of explicit information,
but you can look through it for inspiration as to why it throws an error.

The "loose files backup" is stages in C:\System Volume Information\Windows Backup\Staging
but you'll get Permission Denied if you try to look in there. The loose files in
your homedir, are stored as small ZIP files. They're not normal ZIP files either -- in
cases where a file exceeds the storage capacity of one of their ZIPs, the
second ZIP is in "concatenation" format, meaning catting file A,B,C to a
decompression utility, recovers the file stored in there. They don't make
numbered files like a real ZIP tool might.

The "loose files backup" is slow as molasses flowing up hill on a cold day.
It runs at around 1.5MB/sec.

The second phase is the system image, stored in .vhd files on the backup
drive. You'll get a permissions prompt, but as Administrator (elevated user)
you can at least get in there after clicking the OK button at each level.
VHD files can be mounted various ways, and you can use 7ZIP from www.7-zip.org
to look inside a VHD, if you run out of other ideas.

Anyway, the most likely issue, is the backup drive details changed somehow.

Using the reset script, then format the backup drive, that nukes everything
that I've been able to find so far.

This was hard to study, because my copy of Procmon kept crashing when
I was searching for the write to MediaID.bin . I still haven't figured
out what the 16 byte number in there is for... It seems, while the backup
was running, there was something about a Zoom install folder, the details
of which when recorded in Procmon, made Procmon unhappy later on. I've had
to do the stupid backup over and over, to get a good trace.

Paul