I have exactly the same problem since a week or two. It's a task that I've performed hundreds of times over the last couple of years and now it suddenly doesn't work: I open a scanned pdf file (typically 100-200 pages, 40-70 MB), expand the thumbnail preview to verify that all pages are there, remove the PDF/A protection, save and close the file. I can do two files, when I open the third file I always get the "our of memory" message and the program freezes. Before, I could dozens of files in a row and never had the problem.
The issue is reported to our engineering team and they are working on it to find the fix. We will share the update once we will hear anything from them.
Hope you are doing well and sorry for the trouble. As described, when you try to preview the pages on PDFs it constantly fills up the RAM and you can not load more pages.
Please go to Edit (Win) , Adobe Acrobat (Mac) > Preferences > Page Display > Under Rendering, uncheck 'Use page cache' > Click OK and reboot the computer once and see if that works.
- Would you mind sharing the steps you are doing to preview the PDF pages? - Is this a behavior with a particular PDF file or with all the PDFs? Please try with a different PDF file and check. If the file is stored on a shared network/drive, please download it to your computer first and try again.