Hi Sirin did you follow Wolfpack345 installation guide link below
Also ive been thinking of any possible issues that might cause CTD on your Setup.
1. Did right click on your SH3 exe and change compatabilty settings to windows 7 and click on run as administrator and Apply
that worked for me on my all AMD gaming rig amd 3800x 32 gig ram asrock taichi RX 6800 TX gpu windows 10 Pro
2. Do you have another SH3 install using the SH3 save folder in your documents
if so change your GWX KC save Folder to something different eg KCC (Knights Cross Campaign for short) in MultiSH3 tool 3 blue uboat icons in your GWX KC install Folder
3. Also did you install GWX KC outside Program Files X86 (Windows security will cause you problems if installed there)
I made a seperate installation folder on drive C:/ but outside Program Files X86 all is good.
4.Did you active Hsie Patch and activate it by clicking ok and did you get a text popup SH3 Patched.
Please let us know if you fixed your issue Sirin
Kind Regards blackswan40