Windows 10: Can't "safely remove" external hard drive, dllhost.exe holding lock

Hi I have an external hard drive that is almost permanently plugged into my laptop to do a daily scheduled backup. The "safely remove" option never works though, I always get the "This device is currently in use" error. I ran Process Explorer and searched for the drive letter. I saw that dllhost.exe was holding two locks to the root directory. When I manually closed these handles, then I was able to safely remove the drive. The dllhost's command line was: C:\WINDOWS\System32\DllHost.exe /Processid:{DFB65C4C-B34F-435D-AFE9-A86218684AA8} When I looked in regedit for this GUID, I found it referenced in this key: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AFC7B6DE-D642-41B7-AB0C-A01019510741} Values: (Default) REG_SZ Plan9FileSystemAppID REG_SZ {DFB65C4C-B34F-435D-AFE9-A86218684AA8} In the Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AFC7B6DE-D642-41B7-AB0C-A01019510741}\InProcServer32 key I saw a value (Default) REG_SZ C:\Windows\System32\vp9fs.dll Looking at vp9fs.dll I see that it has a Microsoft Windows digital signature and looks legit. Googling the "plan 9 file system" seems to give results for some obscure file system. I don't understand why this dll is holding a lock on my external hard drive. Is there some way to stop this? Windows version: 20H2 build 19042.985.

:)

 

Can't "safely remove" external hard drive, dllhost.exe holding lock

Hi

I have an external hard drive that is almost permanently plugged into my laptop to do a daily scheduled backup. The "safely remove" option never works though, I always get the "This device is currently in use" error.

I ran Process Explorer and searched for the drive letter. I saw that dllhost.exe was holding two locks to the root directory. When I manually closed these handles, then I was able to safely remove the drive.

The dllhost's command line was:
C:\WINDOWS\System32\DllHost.exe /Processid:{DFB65C4C-B34F-435D-AFE9-A86218684AA8}

When I looked in regedit for this GUID, I found it referenced in this key: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AFC7B6DE-D642-41B7-AB0C-A01019510741}
Values:

• (Default) REG_SZ Plan9FileSystem
• AppID REG_SZ {DFB65C4C-B34F-435D-AFE9-A86218684AA8}

In the Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AFC7B6DE-D642-41B7-AB0C-A01019510741}\InProcServer32 key I saw a value (Default) REG_SZ C:\Windows\System32\vp9fs.dll

Looking at vp9fs.dll I see that it has a Microsoft Windows digital signature and looks legit. Googling the "plan 9 file system" seems to give results for some obscure file system.

I don't understand why this dll is holding a lock on my external hard drive. Is there some way to stop this?

Windows version: 20H2 build 19042.985.

 

Cannot Safely Remove External Drives


Open Device Manager, find "disk drives" and your "external drive" in the list of devices, uninstall the driver for your hard drive and then you can safely remove it. The device driver for your external drive "SHOULD" reinstall automatically next time you want to use the drive.

 

Safely Remove Hardware - Windows 10

Hi Grant,

Thank you for posting your query on Microsoft Community.

I understand that you have concern about the how to safely removal of external device from Windows 10. I apologize for the inconvenience caused to you.

I suggest you to provide you valuable suggestion in the feedback app.

1. Click on Search bar.

2. Type "Windows Feedback" without the quotes in the search bar and click on it.

3. Then provide your suggestion.

We can also removely safely the external pen drives or external hard drive through below steps.

1. Open File Explorer.

2. It will show the list of Drives available on the computer, then right click on the external drive which you want to remove safely.

3. The click on Eject option from the list.

Let us know if you need any further assistance on Windows related issues and we will be glad to help.