Microsoft has warned IT and system admins that a file copying, saving, and attaching issue is affecting applications on Windows 11 as well as Windows 10. Thankfully, File Explorer is unaffected, however, 32-bit applications are.
Microsoft says that 32-bit apps that are large address aware and use the CopyFile API are affected. This API essentially helps copy a new file to an existing file and keeps track of the progress. Hence, with this functionality broken at the moment, copying and saving have become a major issue at the moment for affected applications.
Microsoft has also added that 32-bit versions of Office apps like Word and Excel are affected as well, and users may receive a "Document not saved" error. Microsoft explained the issue in detail on its Windows health support page:
You might have intermittent issues saving, or copying, or attaching files using 32-bit apps which are large address aware and using the CopyFile API. Windows devices are more likely to be affected by this issue when using some commercial/enterprise security software which uses extended file attributes. We are not receiving reports that copying files using File Explorer is affected, but CopyFile API used within apps might be affected. Microsoft Office apps such as Microsoft Word or Microsoft Excel are only affected when using 32-bit versions and you might receive the error, "Document not saved." This issue is unlikely to be experienced by consumers using Windows devices in their home or on non-managed comercial device. Note: Apps are not affected by this issue if they are 64-bit or 32-bit and NOT large address aware.
There is a positive though. Microsoft says the issue is intermittent which means redoing the same action could likely work out. The company lists this as a potential workaround:
Workaround: To mitigate the issue, you can attempt to save or copy again. Since the issue is intermittent, it is likely to succeed on a subsequent try.
The above workaround is only for Windows 11 22H2 though. For other versions of Windows 11 and Windows 10, Microsoft recommends doing a known issue rollback (KIR):
Workaround: To mitigate the issue, you can attempt to save or copy again. Since the issue is intermittent, it is likely to succeed on a subsequent try. Important: If the resolution below does not resolve intermittent save or copy issues in your environment, then you might be experiencing a different issue with similar symptoms.
Resolution: This issue is resolved using Known Issue Rollback (KIR). Enterprise-managed devices that have installed an affected update and have encountered this issue can resolve it by installing and configuring a special Group Policy. The special Group Policy can be found in Computer Configuration -> Administrative Templates -> .
Group Policy downloads with Group Policy name:
Download for Windows 11, version 21H2 - KB5023774 230222_032017 Known Issue Rollback
Download for Windows 10, version 22H2; Windows 10, version 21H2 - KB5023773 230222_032013 Known Issue Rollback
Important: You will need to install and configure the Group Policy for your version of Windows to resolve this issue.
In somewhat related news, Microsoft recently resolved a SMB file copy issue on Windows 11 21H2 with the KB5026436 preview update.