GW2014 client crash when trying to mail or job etc

I am writing this, though there is some old entries for this bug, but it was really difficult for me to find the right "appcrash" forum entry and since there hasnt been one for this bug under the groupwise 2014 clients folder, i want to help others who run into the same problem.

We migrated a company from GW 8.03 to GW 2014 SP1. Most of the Clients were Windows XP Sp3.
About 2 % of the migrated users reported recurring client crashes on their personal workstations.
Whenever the user logged into the Groupwise client and tried to compose / write a new Mail / Job / Appointment or whatever it was, the Client crashed by just disappearing from the screen. No Appcrash Notice, nothing, just gone !
The error also happened when with the same Windows user, a different Groupwise user was logged in, so it was a workstation specific problem.
Sometimes when crashing, there was an error documented in the Windows App protocol:
Source: .NetRuntime
Application: grpwise.exe
Framework version:
Description: The process was terminated due to stack overflow

So i thought it could be a .net runtime problem with versions.
We tried uninstalling the client clean, and reinstalled a new one, also checked a newer support build from Novell.
Then we completely reinstalled .net or checked if there maybe was some Microsoft patches that could have caused this.
Nothing helped.
Logged in with a different Windows user and TADA it worked. Problem was, that the users had really big user profile data or had important user profiles, which we didnt want to recreate or reinstall.

The problem persists from old clients being on those workstations which created user defined spell checker files. (Old Data from Gw7 or 8 or 2012)
These defunct files are in the user profile at:

%Userprofile%/Local Settings / Appdata / Novell / Groupwise (WinXP)
Users\%username%\AppData\Local\Novell\GroupWise (Win7)

For german language this was:

and for us- english it was:

DELETE these files and you are all done. (you can also move them for backup)

Looks like this can happen on Windows XP as well as on newer OS, Windows 7 for example.