KBA-01881: Server Error Value Cannot Be Null

Question:

My user has reported a server error which says Value cannot be null. Parameter name: stream.  What do I do?

Answer:

This error is caused when the IIS server cannot persist state to the file system.

Single node deployments:

• Check to see if the drive on the IIS system is full or corrupt.
• Reboot, because that fixes all sorts of issues.
• See below for how to know what path the Web Application is using.

Multiple IIS nodes:

Because the nodes might share a common file store, see the Members tab in ICTool, specifically the PDS and FDS path values.

1. Verify that the drive is still accessible at the specified path.
2. Check if the drive is full or corrupt.
3. Reboot the VM with the shared drive.
4. Reboot the IIS node that cannot access the file share.

KBA-01881; Last updated: September 9, 2025 at 9:36 am