LucasMacBeth-0013 avatar image
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LucasMacBeth-0013 asked LeilaKong-MSFT commented

FSLogix will only mount the first 4 Profiles

I have an issue where FSLogix will only mount the profile for the first 4 users that sign into my RD Session Host. We have had this in place for the past 6 months with no issues and they have only just started.

When the 5th user goes to sign in the user hangs on the Please wait for the FSLogix Apps Services, this eventually times out and the user signs in with a Local Profile.

The Main errors I get in the FSLogix Profile Logs are:

ErrorCode set to 121 - Message: The semaphore timeout period has expired.
AttachVirtualDisk error (The semaphore timeout period has expired.)

If I sign out of a working profile then I can sign in with any other user immediately.

I have already done the following:
- Fully reinstalled FSLogix Apps
- Can replicate this issue with all fresh VHDX files.
- Removed all registry keys under HKEY_LOCAL_MACHINE\SOFTWARE\FSLogix
- Tried an older version of FSLogix and got the same issue.

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1 Answer

LeilaKong-MSFT avatar image
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LeilaKong-MSFT answered LeilaKong-MSFT commented

Hello @LucasMacBeth-0013 ,

1.Did you set maximum session for the session host as 4?

2.The following articles may be helpful for your issue:

"I disabled the delta disk (rw.vhdx) ,disabled mulit mountof the Profile (so only one rds can Host the Session) and set a logoff of the User after idle time."

"The problem is likely to be caused by a file system problem on the source drive that is being imaged.

Run 'chkdsk c: /r' from a command prompt.
Note: Replace 'c:' with the drive letter that you are imaging."


Best regards,

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Hi @LeilaKong-MSFT

  1. No the maximum sessions has not been set, the users still logs in but gets a Temp Profile.

  2. We are using direct access to the VHDX, differencing disks are not being used.

  3. CHKDSK are clear (No issues).

What we have done is restored the Remote Desktop Server back 2 days before the issue started, this resolved the issue. The following morning the issue returned, looking back at our logs the only things that had installed/updated since the restore were the following:

  • Windows Update: Installation Successful: Security Intelligence Update for Microsoft Defender Antivirus - KB2267602 (Version 1.335.459.0)

  • Package Microsoft 365 Apps for enterprise - en-us updated from 16.0.13801.20360 to 16.0.13901.20336

We restored the Server back again and disabled updates for Microsoft Office 365 Apps for Enterprise, so far the Server has been working fine since Friday 09/04/2021, Looks like an Office 365 Apps upgrade could be the cause of the problem.

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Hello @LucasMacBeth-0013 ,

Thanks for your sharing. You've done a great job!

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