I followed Doreen's comment below re: "check for updates" and it seemed to fix this issue for me!
"Doreen commented · November 06, 2019 16:16
Removing the SLstore file didn't work for me...
I then opened a pdf with Adobe, before it closed, went to the Help menu, went to the bottom of the list and clicked "Check for Updates". It did a several minute update and after a few more prompts to get the system reorganized, my PDF has stayed open for over 10 minutes now. Hope it works tomorrow."
I followed Doreen's comment below re: "check for updates" and it seemed to fix this issue for me!
"Doreen commented · November 06, 2019 16:16
Removing the SLstore file didn't work for me...
I then opened a pdf with Adobe, before it closed, went to the Help menu, went to the bottom of the list and clicked "Check for Updates". It did a several minute update and after a few more prompts to get the system reorganized, my PDF has stayed open for over 10 minutes now. Hope it works tomorrow."