Windows Server Backup keeps failing

Question

Windows Server Backup keeps failing

Green Hat 0

Hi, we are having issue with the "Windows Server Backup" . It keeps giving us an error The semaphore timeout period has expired - Unknown Error (0x8004245f)

In the event viewer I can see Backup error '0x807800C5' (There was a failure in preparing the backup image of one of the volumes in the backup set.). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.

So far I've tried :

Deleting the old Shadow Copy
Check disk
Reinstalled "Windows Server Backup" Role
Rebooting the VM.
Backing up to a different location (local and remote).

Anything else that I should try?

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Answer 1

Hello Green, I am Henry and I want to help you with your issue.

The two error codes you provided are the key.

0x807800C5 (Failure in preparing the backup image): This means Windows Server Backup asked the Volume Shadow Copy Service (VSS) to create a point-in-time snapshot of your drive(s), and VSS failed to do so.
0x8004245f (The semaphore timeout period has expired): This is the reason VSS failed. A specific component that VSS was waiting for (a VSS "writer") did not respond in time, causing the entire operation to time out.

Please perform the following steps in order.

Step 1: Identify the Failing VSS Writer. This command will tell us precisely which service or application is causing the timeout.

Run the command Command Prompt as Administrator on the server: vssadmin list writers
Examine the output for any writer that does not show State: [1] Stable and Last error: No error.
If you find a writer in a "Failed" or other error state, you have found the cause. Note the "Writer name" and restart the corresponding service.

Step 2: Check for a Corrupted Backup Catalog. Sometimes the existing backup set is corrupted, preventing new backups from being written.

Navigate to your backup destination (the local drive or network share).
Locate the folder named WindowsImageBackup.
Rename it to WindowsImageBackup.old.
Try running the backup again. If it succeeds, the old backup set was the problem.

Step 3: Check Hypervisor Integration Services. Since this is a VM, the VSS process is coordinated by the hypervisor's tools.

On Hyper-V: Ensure Integration Services are up to date. You can also try reinstalling them from the Hyper-V console.
On VMware: Ensure the latest version of VMware Tools is installed and running. A common fix is to use the "Programs and Features" control panel inside the VM to "Repair" or "Reinstall" VMware Tools.

Step 4: Let's ensure there is no underlying OS file or disk corruption.

In your elevated Command Prompt, run sfc /scannow.
After it completes, run DISM /Online /Cleanup-Image /RestoreHealth.
While you have run chkdsk before, it is worth running it on the small, hidden System Reserved / Recovery partitions if they exist. You can assign them a temporary drive letter in Disk Management to do this.Please perform the following steps in order.

Hope one of these works for you.

Green Hat 0 Reputation points

2025-08-11T00:09:01.7366667+00:00

Hi Henry,

I've tried all the above but I am still unable to run the it.

No VSS error.

Deleted the old backup even tried backing up to a different location.

Contacted both my backup provider and hypervisor , they said its a Microsoft issue/error.

Ran both check and there was no error.

Anything else that I could try?
Henry Mai 2,375 Reputation points Independent Advisor

2025-08-11T07:00:36.32+00:00

Thank you for your patience and for confirming you've completed all those initial steps. The next most likely cause for a "semaphore timeout" when all VSS writers are stable is a conflict between different VSS engines, known as "providers."

Could you please perform the following single step and share the result?

Run the command as Administrator: vssadmin list providers

Please copy and paste the full output from that command in your reply.

The output will tell us if your backup provider (or another application) has installed its own VSS provider that is conflicting with the default Microsoft one.

Besides that, could you please share a screenshot of the error and the Event Viewer logs from the time it occurred? Based on what we see, we will know the exact next step to take.
Green Hat 0 Reputation points

2025-08-12T00:04:54.4466667+00:00

Hi Henry, please find the result below. Let me know if you need anything else.

PS C:\Windows\system32> vssadmin list providers

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001-2013 Microsoft Corp.

Provider name: 'Microsoft File Share Shadow Copy provider'

Provider type: Fileshare

Provider Id: {89300202-3cec-4981-9171-19f59559e0f2}

Version: 1.0.0.1

Provider name: 'Microsoft Software Shadow Copy provider 1.0'

Provider type: System

Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}

Version: 1.0.0.7

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Windows Server Backup keeps failing

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