GrandPerspective is very stable. Occassionally, however, users report hangs while scanning. If you think the app hangs while scanning, follow these steps:

1. Enable Full Disk Access. Some users have reported that doing so resolved the hangs that they experienced. It anyway is good to have this enabled, as it lets GrandPerspective scan more of your disk contents.
2. Check that there is not a dialog asking for permission to access certain data. The first time you scan using (a new version of) GrandPerspective, the app needs permission to access certain content. Scanning is paused until you grant or decline the request.
3. Check that you have version 3.5.2 or higher. Earlier versions could have issues scanning folders with cloud content. Scanning these folders could trigger downloads of dataless files. This could take so long that the app appeared to hang. This has been fixed in version 3.5.2.
4. Enable full logging when starting the application. To do so, start the application from Terminal with -logAll YES as commandline argument.
   
   For example, when you installed it in your Applications folder type:
   /Applications/GrandPerspective.app/Contents/MacOS/GrandPerspective -logAll YES
5. Try to reproduce the hang. Did you manage?
   • No, keep trying. Go back to Step 4.
   • Yes, then inspect the logging in the Terminal to determine which folder it is trying to scan when the hang happens. Continue to Step 6.
6. Try to find the root cause by answering the following questions:
   • Is it repeatable? Does it always hang while scanning the same folder?
   • Is there anything special about this folder?
7. Once you manage to reproduce a repeatable hang, submit a bug report for it. Provide as much details as you can. This should include the steps to reproduce, but also the version of GrandPerspective and your version of macOS.
   
   Note: You can also submit a report when you did not manage to reproduce a repeatable hang. However, the chance that the problem can then be fixed is much smaller.