A. 1. Free up storage space: Go to Settings > General > iPhone Storage and check if you have enough free space. If not, delete unnecessary apps or files to create space for Planimeter Pro. 2. Update the app: If you can access the App Store, check if there is an update available for Planimeter Pro. Updating can fix bugs that cause the app to malfunction.

B. 3. Reset all settings: Go to Settings > General > Reset > Reset All Settings. This will not delete your data but will reset system settings, which may resolve the reinstalling issue.