SharePoint or OneDrive Backup fails with 'Cannot complete this action'
| KB ID: | 4793 |
| Product: |
Veeam Data Cloud
for Microsoft 365 Veeam Backup for Microsoft 365 | 7a | 8 | 8.1 | 8.2 | 8.3 | 8.4 | 8.5 |
| Published: | 2025-11-21 |
| Last Modified: | 2026-08-10 |
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Challenge
A backup attempt for SharePoint Online and OneDrive objects may fail with the following message:
Cannot complete this action. Please try again. Total count of failed items: N
Underlying Error:
Server error of type Microsoft.SharePoint.SPException occurred: (-2147467259) Cannot complete this action.
Cause
Enumeration requests issued during SharePoint Online and OneDrive backup are processed by the SharePoint Online service, and the success of any individual request depends on the capacity available to the service infrastructure, the size and complexity of the request, and the volume of content being evaluated. Because these factors interact, an identical request against the same site can complete while the infrastructure is under low load and exceed the processing limits of the service when demand is higher. This behavior is most commonly encountered when a SharePoint incremental crawl processes more than 150 item changes, which increases the processing required to complete the request.
Solution
Veeam Backup for Microsoft 365 Customers
To remediate this situation for Veeam Backup for Microsoft 365 deployments, update the OneDriveChildPageSize value using Set-VBOConfigurationParameter.
The OneDriveChildPageSize parameter is a backup proxy configuration setting that controls the page size of the CAML queries used during SharePoint and OneDrive backup operations, specifically for folder-children expansion and client-side item enumeration. Adjusting this value changes how items are requested from the SharePoint Online service during enumeration, so that each request remains within the processing limits of the service and the timeouts that cause these backup failures are avoided.
Use the following variables with the example scripts in KB4888: How to Apply Custom Settings in Veeam Backup for Microsoft 365 Using Set-VBOConfigurationParameter to configure this setting for each backup proxy or proxy pool that is running an affected backup.
Veeam Data Cloud for Microsoft 365 Customers
This configuration change has already been applied on the backend, and no customer action is required.
More Information
Similar Issue from February 2026
Challenge
A backup attempt for SharePoint Online and OneDrive objects may fail with the following message:
Cannot complete this action. Please try again. Total count of failed items: N
Underlying Error:
Server error of type Microsoft.SharePoint.SPException occurred: (-2147467259) Cannot complete this action.
Cause
After review with Microsoft Support, it was confirmed that affected tenants may encounter this issue, as described in event OD1177143 on the Service Health Dashboard in the Microsoft 365 admin center.
Direct Access Link:
Service Health Dashboard - OD1177143
Solution
Microsoft has confirmed via events OD1177143 and SP1177145 in the Microsoft 365 admin center that a fix was deployed to resolve this issue. As of February 20, 2026, Microsoft has confirmed that the problem is now considered resolved.
If your organization is experiencing this backup issue, please get in touch with Microsoft Support for further assistance.
If this KB article did not resolve your issue or you need further assistance with Veeam software, please create a Veeam Support Case.
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