I have 2 windows 10 systems where Acrobat reader has been set to ALWAYS be the default application for PDF files. It will open 2-5 PDF files and then stop opening PDF files at all until a system restart is conducted. Acrobat Reader tasks persist in task manager and ending them does not improve the situation. I could really use some help. I have tried the adobe Acrobat uninstaller and re-installer. No joy. No other google remedies seem to preseent themselves.