Save windows all white, no button

@fdouin wow, that's all of scanned pages, 500-1000?! How much RAM do you have? When you save the scanned pages, what resolution did you save it at? Maybe try closing all unnecessary applications to free up as much RAM as possible, including those that are streaming movies or music in the background. Because you are scanning so many pages, do you even have the disk space to do it? Make sure you have plenty of free hard drive space on the drive where you're trying to save. Acrobat needs temporary space for processing too. 

Personally, I would scan in smaller chunks, and combine the pages after the scan or, reduce the resolution of the scans too.