Thank you, John. I will try that.
Here is interesting thing. I realized that for a patient there was one pdf file if I click on it to open, AC freezes. To avoid this freezing temporarily, I went to the path:
windows explorer--> program files--> Amazing charts--> Imported Items--> (patient acct number). There I changed the icon view to preview Thumbnails (or large icon). I could see which lab results I wanted (because file names are just the numbers).
I will try to delete this problematic scanned pdf file and re-import the file to see if that solves the issue. Also I realized that the size of the imported items folder for the patient was large. May have to optimize the size.