I have an external hard disk, which got accidentally formatted during a system restore. This hard disk is quite large and once there were millions of JPG's stored, which got deleted a long time before. However, I do not need this JPG's anymore and with a deep scan it seems, they are still able for recovery.
Running Recuva in deep scan mode takes ages and always cancels at some point (insufficient memory, etc.).
Is there a way to run Recuva with all functionality in deep scan mode and search for all files EXCEPT for files with the extension JPG?
No, and it wouldn't make the scan any faster. The deep scan has to examine the header of every cluster it finds to determine if it contains a valid file header, and if so add it to Recuva's dynamic list. So if you don't want jpegs then all the clusters would still have to be searched to check that they had a file header, and then discarded if the header was jpeg.
You can run a deep scan once, with nothing in the file/path box, and then filter the results afterwards by whatever file extension you want, altering the filter as you go.
Running a deep scan with a filter applied might enable the run to complete without memory problems, but that's something I can't test.