Windows 10: Unified Write Filter Blue Screen Thread exception uwfs.sys

We are using write filter on Windows 11 education and recently when uwf is enabled, all of the systems will will reboot to a blue screen error for thread exception for uwfs.sys. The only way we found to recover from this is to reboot to a windows recovery disk and rename uwfs.sys. We are not sure what changed where. I have checked the file and registry exclusions. Any advise or help will be greatly appreciated! uwfmgr volume protect c:uwfmgr overlay set-type diskuwfmgr overlay set-size 10240uwfmgr overlay set-passthrough onuwfmgr overlay set-criticalthreshold 10000uwfmgr overlay set-warningthr

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Problem when enabling Firewall (with Firewall exceptions) and Unified Write Filter (with UWF exclusions)

Hello,

I have a problem when enabling Firewall (with Firewall exceptions) and Unified Write Filter (with UWF exclusions). I have observed this problem in the following Windows 10 versions:

- Windows 10 Enterprise 2016 LTSB 1607

- Windows 10 Enterprise 2019 LTSC 1809

The Windows 10 machine is configured as follows:

- There is an application 'X' installed in "C:\folderX" directory.

- Firewall is enabled. Application 'X' is added as an exception to Firewall.

- UWF is enabled, C:\ drive is protected by UWF and "C:\folderX" directory is added as an UWF exclusion.

- Application 'X' needs to communicate with other external machines/applications via Ethernet Network interface.

The following two scenarios are observed:

a) If both Firewall and UWF are enabled, Application 'X' does NOT communicate with external machines/applications.

b) If Firewall is disabled or UWF is disabled or both are disabled, Application 'X' does successfully communicate with external machines/applications.

How can I solve the issue in scenario a)? This is, how can I have Firewall and UWF both enabled at the same time and Application 'X' communicating to external machines/applications?

Is this a known bug to Microsoft? If yes, is there any fix?

Thanks.

 

Unified Write Filter (UWF) and BGinfo - Running both in Windows 10

Hello, I have a machine with Windows 10 Enterprise 2016 LTSB operating system. I am using BGinfo application to add some information into Windows Desktop Background (BootTime, HostName, UserName, Domain, etc). The Unified Write Filter (UWF) is set to protect
the C: drive where Windows operating system is installed (some folder/file exclusions have been set for UWF). There is only one user account ("Administrator" user).

When UWF is disabled, BGinfo works fine and updates Windows Desktop Background.

When UWF is enabled, BGinfo is not updating Windows Desktop Background. There seems to be some incompatibility.

Can anyone please help? Thanks.

 

Regarding UWF (Unified Write Filter)

I have some HP thin-client where Windows 10 Enterprise LTSB custom image is installed. These clients having 4 GB RAM is installed and 2.9 GB is usable because of video memory.

As we know in the write filter environment all writes are in overlay and system must reboot to clear the overlay memory otherwise system will get crashed after overlay exhausted.

In this OS we have only one drive C which is protected by UWF and additional drive Z which is RamDisk for temporary writes and maximum of 768 MB, so its not possible to create page file in protected volume because while enabling UWF page file don't exist
any more and the other drives are Z very less in memory.

Now using some tool while booting OS, i have moved 8GB of partition from c drive and created additional drive D which is not protected then configured page file range 4.5 GB to 7GB in this drive after enabling the UWF still page file present and working.

Now i have know UWF overlay size and how to calculate the system UP time which is depend upon the size of the overlay size.

Is it good to set 600 MB or 1000 MB for overlay size and what are the UP times, now system is not complete running as i can see in it used overlay memory in 2 days around 100 mb ?

Thanks in advance.