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An error occurred while saving the commentAndy White commented
I have this issue also;
1. Acrobat Version 2018.011.20040
2. macOS 10.12.6
3. Time to display comments panel: 30 secs (Current file has 33 comments)
However this is independent of the amount of comments contained in a PDF as it still takes 30 secs even when the PDF on my mac contains no comments.