Why is InDesign being unbearably slow?

[Jane FS]

I've used Indesign for many years now and this used to work fine with no problems.  I'm currently using Indesign 2021 which for the past few months has been horendously slow and sluggish. I have an almost brand new Macbook Pro with an 8TB HD and 64GB of Memory and am using MacOS Catalina Version 10.15.7.  Even extremely simple tasks that should take a few minutes end up wasting about 20 minutes of my time. Why is InDesign being so slow and how can I fix this?

[Eugene Tyson]

Try resetting your preferences

https://helpx.adobe.com/ie/indesign/using/setting-preferences.html#restore_all_preferences_and_defau...

Try creative Cloud cleaner  tool.

https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

[Scott Falkner]

I had an InDesign file that was being very slow and sluggish for me about a year ago on my older (2013) iMac. I discovered I had some complicated GREP Styles defined. InDesign was processing all the text in the file using the GREP Styles and it was slowing everything down. I duplicated the styles and removed the GREP from the duplicates. I use Find/Change to replace the original styles with the duplicates, then again to cahnge them back aafter editing. Fortunately the GREP was only changing colour so I didn’t have to worry about text reflowing.