Large file copies in Windows 11 22H2 take longer than usual due to a problem, this appears to be related to the 'cache manager' (buffered copy).

When trying to copy files that are many gigabytes in size, this issue may arise. However, this is not limited to copying from a remote location; it can also occur when copying local data. According to Microsoft (1) , (2) Knowledge Base (KB5017389), this appears to be related to the 'cache manager' (buffered copy).

Copying large multiple gigabyte (GB) files might take longer than expected to finish on Windows 11, version 22H2. You are more likely to experience this issue copying files to Windows 11, version 22H2 from a network share via Server Message Block (SMB) but local file copy might also be affected.Windows devices used by consumers in their home or small offices are not likely to be affected by this issue.

It is unclear exactly how much slower it is, but one user on a Microsoft support site claims that it takes him at least twice as long to copy. Microsoft has been tasked with developing a fix.

Bug in Windows 11 22H2; copying large files may take longer.