After installing IDE 2.3.1 I am not able to save (new) sketches.
After Ctrl-S (File>Save) no message is given. When closing the IDE/Sketch, it closes without any message.
When re-opening the sketch the modifactions are not there.
Using Save-As I get an error message:
pathname\filename
File Not Found
Check the file name and try again.
I moved your topic to an appropriate forum category @ducati999.
In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.
Is that the exact message, or did you replace the real path with pathname\filename?
The problem you are experiencing might be related to some special characteristic of the path under which you are attempting to save the sketch. Is there anything special about this path? For example, is it on a network share, or on a cloud storage service, or on a RAM drive?