CLEAN BOOT

Error writing file C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\bin\airfilter.dll

 1. If not, please follow the steps below:

1) Run CMD as administrator.
2) Type the full path of the update file, and then press Enter.
You could refer to this article for specific steps:Description of the security update for Microsoft Exchange Server 2019 and 2016.
2. If it is installed as an administrator, please follow the steps below:
1) Please try to restart your computer in the clean boot and see if the issue is resolved. Please note if the issue is resolved, reset the computer to start normally.
About how to perform a clean boot you could refer to:How to perform a clean boot in Windows.
2) Please try to unregister and reregister Windows installer.
a) Click on "Start" > "All Programs" > "Accessories" > "Run", type msiexec /unregister, and then press Enter.
b) Click on "Start" > "All Programs" > "Accessories" > "Run", type msiexec /regserver, and then press Enter.
c) Reboot your computer and see if the issue is resolved.
There is a similar case you could refer to:ERROR 1310.