Import stops after few seconds

Hallo everyone, 

for a few days i have an issue importing photos into my usual catalog. I start the process and after about 4 sec it stops. No error, it just stops. 

I tried so far: 

- deinstalling and reinstalling Lightroom classic -> no change

- optimizing the catalog -> no change

- exporting -> it works

- import doesnt work either from the laptop directly or from an external drive -> no change

- creating a new catalog -> no change

Now i am at my wits end. Anyone here who can help?