Hi Albert,
I assume you have the latest version of Cinema 4D. Not that I was able to find this issue anywhere mentioned for older versions.
The key question, are these fields grayed out or present them self normal?
Is there anything that happens right before it turns to the problem?
Are you able to use the little triangles near the parameter field?
Can you call up a fresh scene and it happens there then already?
If you can save, close and open the scene file, does it persist in the file.
Has the drive you are working on all the needed permissions?
Yes, as Ricky Sharp mentions, check with the support, if you have that problem, save the file.
https://www.maxon.net/en/support-center
The only problem that I can remember is based on Google’s Chrome. Is that app running in the background?
Another typically suggestion is, to dis-connect all cables, replace the only needed input devices and start in safe mode.
Sorry about your troubles.
All the best