Windows 11

Microsoft has addressed a known issue leading to significant performance hits when copying large files over SMB after installing the Windows 11 2022 update.

"There is a performance reduction in 22H2 when copying larger files from a remote computer down to a Windows 11 computer or when copying files on a local drive," explained Microsoft's Ned Pyle when acknowledging the issue more than a month ago in early October.

Even though Redmond did not provide any information on the actual decrease in performance on affected systems, the amount of time needed for file operations could more than double in some conditions, according to user reports.

However, it did share on September 30 in the KB5017389 preview update support document that Windows devices used in home networks or small offices are less likely to be impacted by this issue.

"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," Microsoft added.

Almost two months later, the company issued a fix rolling out to systems enrolled in the Windows Insider program.

"The preview fix for this issue is now available in Windows 11 Insider Preview Build 25252," Pyle said on Monday.

"The final fix for Windows 11 22H2 production computer will come in a normal monthly Cumulative Update through Windows Update once validated in Insider builds."

Workaround available

Microsoft also shared a temporary solution affected customers can use to work around the file copy performance hit.

As it explains, users can mitigate the file copying over SMB issues with the help of file copy utilities that don't use cache manager (buffered I/O).

To do this, you can use the built-in robocopy and xcopy tools with the template commands listed below:

robocopy \\someserver\someshare c:\somefolder somefile.img /J

OR

xcopy \\someserver\someshare c:\somefolder /J

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