Processing OneDrive finished with warning: Cannot complete this action

[FCU_JE]

According to support, it still does an incremental backup, not a full.

Support would disagree with the manual then:

https://helpcenter.veeam.com/docs/vbo36 ... parameters

"Defines that the backup job session is considered a full run."

[FrancWest]

True, but after the jobs completed, I didn't see a huge increase in storage usage. Perhaps a full run is only scanning all files and not backing them up if they exist already.

[nracinelogic]

Can add to the pile of affected orgs.

A few of our customers are affected, with no growth in users affected in the past few days.

[CurtisC]

create an extra Job for the affectedt sharepoint sites and run this job with:
Get-VBOJob -Name "Backup job name" | Start-VBOJob -RunAsync -Full

^I can confirm this works for two days then fails.

Unfortunately we have 30+ companies backing up that are failing with the OneDrive/Sharepoint errors. Companies outside of mine are reporting same failures.

Case 04043180

Hopefully a fix is in this works.

Curtis

[spritchard81]

Running the command above does seem to create a successful incremental backup. However seeing the same as others, subsequent scheduled backups still fail.

[FCU_JE]

Veeam has updated https://www.veeam.com/kb4793 today (2026-07-27) with the following:

Update - July 27, 2026
To remediate this situation, update the OneDriveChildPageSize value for each backup proxy or proxy pool that is running an affected backup using Set-VBOConfigurationParameter.

Code: Select all

$xpath = "/Veeam/Archiver/Source"
$key = "OneDriveChildPageSize"
$value = "150"

Note: Ensure that the Veeam.Archiver.Proxy service on the proxy(s) is restarted after the setting is changed by adding the -Restart switch to the Set-VBOConfigurationParameter command.

Example PowerShell scripts can be found in the PowerShell User Guide.

Anyone brave enough to guinea pig it? I'm keen to find out if this remediates the issues just for OneDrive "sites" or if it resolves issues in traditional SharePoint sites too.

[AlexLeadingEdge]

It’s not fixed. At the very top of the article it says:

Yes, my mistake, I read the bottom line and it read like Veeam had taken care of it, but that was in reference to late 2025 / early 2026. I then opened a ticket with Veeam Support because it still wasn't working for me.

[AlexLeadingEdge]

Anyone brave enough to guinea pig it? I'm keen to find out if this remediates the issues just for OneDrive "sites" or if it resolves issues in traditional SharePoint sites too.

I've just tried it and it has worked.

In PowerShell (!!! Update with your hostname !!!):

Code: Select all

$Proxy = Get-VBOProxy -Hostname "YOUR_HOSTNAME_GOES_HERE"
$Credential = Get-Credential

Set-VBOConfigurationParameter `
    -Proxy $Proxy `
    -WindowsCredential $Credential `
    -XPath "/Veeam/Archiver/Source" `
    -Key "OneDriveChildPageSize" `
    -Value "150" `
    -Restart

You can check that it has worked by using this PowerShell command:

Code: Select all

Get-ChildItem "$env:ProgramData\Veeam" -Recurse -Filter Proxy.xml -ErrorAction SilentlyContinue | Select-String -Pattern 'OneDriveChildPageSize'

[AlexLeadingEdge]

I'm not sure if this is relevant, but I've just noticed that this won't work on Veeam Backup for Microsoft 365 version 7a as Set-VBOConfigurationParameter wasn't introduced until version 8.0.

I couldn't update this client as their backup server is still on Windows Server 2012 R2 and Veeam365 8.0 won't install on it.

[ottl05]

I've just tried it and it has worked.

In PowerShell (!!! Update with your hostname !!!):

Code: Select all

$Proxy = Get-VBOProxy -Hostname "YOUR_HOSTNAME_GOES_HERE"
$Credential = Get-Credential

Set-VBOConfigurationParameter `
    -Proxy $Proxy `
    -WindowsCredential $Credential `
    -XPath "/Veeam/Archiver/Source" `
    -Key "OneDriveChildPageSize" `
    -Value "150" `
    -Restart

You can check that it has worked by using this PowerShell command:

Code: Select all

Get-ChildItem "$env:ProgramData\Veeam" -Recurse -Filter Proxy.xml -ErrorAction SilentlyContinue | Select-String -Pattern 'OneDriveChildPageSize'

I edited the xml, so let´s wait end see

[aeph]

Thank you so far. I am running one Windows Proxy (central Management Server) and 5 linux proxies in a pool. What do i need to do? Do i need to run the PowerShell command with -Proxy argument or with -ProxyPool Argument? Its not very clear to me. Thank you!

[NikoWana]

I've just tried it and it has worked.

In PowerShell (!!! Update with your hostname !!!):

Code: Select all

$Proxy = Get-VBOProxy -Hostname "YOUR_HOSTNAME_GOES_HERE"
$Credential = Get-Credential

Set-VBOConfigurationParameter `
    -Proxy $Proxy `
    -WindowsCredential $Credential `
    -XPath "/Veeam/Archiver/Source" `
    -Key "OneDriveChildPageSize" `
    -Value "150" `
    -Restart

You can check that it has worked by using this PowerShell command:

Code: Select all

Get-ChildItem "$env:ProgramData\Veeam" -Recurse -Filter Proxy.xml -ErrorAction SilentlyContinue | Select-String -Pattern 'OneDriveChildPageSize'

Work for me

[cw1972]

I've had a case open since 20/07/2026 (Case # 08165717) and on their advise ran a couple of fulls from the command line which completed, so I thought I had a resource issue on my side.

Now I've caught up with this thread and have just tried the 'OneDriveChildPageSize' fix, let's see how my backups run overnight

[FrancWest]

As suggested by support I edited the proxy.xml at %ProgramData%\Veeam\Backup365\Proxy.xml to add the OneDriveChildPageSize=150 parameter and ran the job again. It completed successfully. Now let's monitor it a couple of days.

[cw1972]

I've had a case open since 20/07/2026 (Case # 08165717) and on their advise ran a couple of fulls from the command line which completed, so I thought I had a resource issue on my side.

Now I've caught up with this thread and have just tried the 'OneDriveChildPageSize' fix, let's see how my backups run overnight

All my backups completed successfully last night, so let hope this is now resolved until Microsoft makes further changes and breaks things again.

[lmendel]

I remediated our Linux proxies using the script from KB and looks like the jobs are running fine:

Code: Select all

$xpath = "/Veeam/Archiver/Source"
$key = "OneDriveChildPageSize"
$value = "150"
$vboproxy = Get-VBOProxy -Hostname YOUR_HOSTNAME_GOES_HERE

$pwd = ConvertTo-SecureString -String "USER_PASSWORD_HERE" -AsPlainText -Force

$linuxcredential = New-VBOLinuxCredential -Account "USER_LOGIN_HERE" -ElevateAccountToRoot -IgnoreFingerprintCheck -Password $pwd

Set-VBOConfigurationParameter -XPath $xpath -Key $key -Value $value -Proxy $vboproxy -LinuxCredential $linuxcredential -Restart