Windows 10 Defender

Although we haven’t seen this here yet, Michael Pook, Geschaeftsfuehrer of C-Technik Software GmbH, reports the following …

Yesterday we had 3 users with a similar problem: CAD4U(-XS) didn’t start anymore, displaying the following  error message ‘CAD4Ulmr Server Class …’.

As far as we have been able to reproduce this effect, it seems to be that on Windows 10 installations with Windows Defender as the only protection software the file CAD4Ulmr*.EXE file will be deleted from the ProgramFiles folder, and without any kind of warning!

This seems to happen with all CAD4U versions from 11 up to 33.

The good thing: it’s more or less easy to solve.


Exclude the whole folder C:\ProgramFiles\C-TECHNIK from being scanned by the Windows Defender.

This can be adjusted in the ‘Windows Defender Security Center’.


Overinstall the CAD4U(-XS) installation with the latest release of the relevant version. This will bring the missing EXE file back and at the same time the latest available version is installed.