This article has general advice on how to proceed in the event that the Android app is crashing persistently. Thankfully crashes are very rare (less than 0.1% of users), but it can be very annoying if it happens to you! So here is what you can do.
First, it is very helpful if you can report the details of your crash, through the Google Usage and Diagnostics settings. In the Settings app, search for the "Diagnostics" setting (it depends on the device, but it us somewhere under privacy) and turn on the Usage and Diagnostics. This means that if the app crashes, google sends us details of the crash.
When you have diagnostics turned on, re-run Memory-Map until it crashes, then if it prompts you to send the crash log to Google, tap Yes. We do analyse all crash logs carefully.
Next, the way to stop the app crashing is to remove the data files that are causing the crash. Nearly all the crash logs we see are due to corrupted map files. So what we need to do is rename the map folder, so that the app does not see any of your map files (we will address how to recover your maps, below).
You will need a File manager app, on your device, or connect the device to a PC so you can use the Windows file manager.
Go to the "Download" folder in the main storage area of your device. You will see a sub-folder in there called "Memory-Map". Rename the Memory-Map folder to something different (like "Memory-MapXXX"). If you have a storage SD card, it is important to REMOVE THE SD CARD from the device. Faulty SD cards are the cause of a large proportion of Memory-Map crashes on Android.
Re-run Memory-Map. It might download a fresh copy of the basemap for your current location. All of your overlay data should still be present. Verify that the app does not crash using just this map.
If it does still crash, then there is nothing for it but to uninstall the app and reinstall from the Google Play store. If you want to save your overlay data, you can back it up by syncing it to the cloud or saving as a GPX file.