What you need to know
- The Windows 11 2022 Update includes a bug that can lower the speed of copying larger files.
- Larger files can see as much as a 40% throughput drop over SMB when reading a file.
- The issue is not within SMB code, but it most likely to be noticed when transferring files over SMB.
Microsoft recently confirmed an issue with the Windows 11 2022 Update that can slow down file transfers. The bug affects multi-GB files and can reduce throughput by up to 40%. The problem is specific to the Windows 11 2022 Update (Windows 11 version 22H2).
"There is a performance regression in 22H2 when copying larger files from a remote computer down to a Windows 11 computer," explained Microsoft's Ned Pyle. "A large (multi-GB file) might see as much as 40% less throughput over SMB when copying down (reading). Copying that same file to a non-22H2 machine (writing) won't see this problem."
It's possible to work around the issue. Pyle outlined the steps in his post. "For a workaround, use robocopy or xcopy with the /J (unbuffered IO) parameter."
Using that workaround will restore the throughput of the previous version of Windows 11.
Pyle notes that the issue isn't within SMB code. Instead, SMB is the most likely scenario in which the problem will be noticed. A user could see the same slowdown when trying to transfer large local files.
This isn't the first issue related to the Windows 11 2022 Update. Last month, PC gamers saw lowered frame rates, stuttering, and other issues after upgrading. NVIDIA later shipped a fix for the bug. Microsoft also confirmed a printer issue with the latest version of Windows 11.
Because Windows updates often have issues in their early days, many people choose to wait to upgrade. In our poll asking if people had installed the Windows 11 2022 Update, only 43.17% said yes.
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Sean Endicott brings nearly a decade of experience covering Microsoft and Windows news to Windows Central. He joined our team in 2017 as an app reviewer and now heads up our day-to-day news coverage. If you have a news tip or an app to review, hit him up at firstname.lastname@example.org.