If you cannot launch Momento or have noticed that data has been lost then these are the steps to help you attempt to try and recover your data.
Momento stores all of its data on your device only unless you have enabled iCloud backup in Momento. We do not have access to your data or any backups.
Data stored in Momento can only be lost if:
Momento is deleted from a device
This can happen accidentally or if your device is synced with a new computer it hasn't previous been synced with. When any application is deleted from a device the application data is also deleted. A warning is displayed when attempting to delete an application notifying the user of this.
Momento's data is corrupt
It's rare that an applications data can become corrupt. This can happen if a process which modifying Momento's data is interrupted. This most often occurs when an iPhone is being restored from a backup and the process is interrupted. It can also rarely occur when an application fails to complete and update. When application data is corrupt the application will attempt to fix the issue itself. If this fails then the app will fail to launch or launch with incomplete data.
If you have a backup of your Momento data...
If you haven't made a backup of your Momento data...
If you haven't made a backup of your Momento data using Momento's Backup Feature then the only option left to possibly recover your data is to restore your device from the last device backup. This will have been made the last time you synced your device with iTunes OR if you have iCloud Device Backup enabled.
You can do this as follows:
1) Do not sync your device with your computer OR backup via iCloud after noticing the data loss or after deleting Momento.
iTunes/iCloud only keeps one backup of your device which is overwritten every time your device backs-up.
Check the date the last backup was made. This can be found in iTunes > Preferences > Devices OR if you backup via iCloud in iOS Settings > iCloud > Backup.
If your device has backed up since the data was deleted or corrupted then the backup on your computer or in iCloud will no longer contain a restorable copy of Momento's data.
If you backup your device via iTunes and have a backup of your computer, check to see if you have a copy of your device backup from before the data loss. The file will be located at ~/Library/Application Support/MobileSync/Backup.
2) Ensure your backups won't be overwritten
To disable this in iTunes go to Preferences > Devices and check the checkbox beside 'Prevent iPods, iPhones and iPads from syncing automatically'.
To avoid this using iCloud you will need to disable iCloud Backup in iOS Settings > iCloud > Backup.
3) Copy data from your device which will be lost in the restore.
Connect your device to your computer (remember to not sync or backup your device) and copy any photos or other data on your device which will be lost by restoring to the previous backup. Photos are often the most important thing to copy (unless you have iCloud Photo Library enabled) as these cannot be replaced.
4) Ensure all your apps are downloaded to your computer
Ensure that all the apps you have on your device are downloaded and available in iTunes. They will need to be there so iTunes can copy them back across to the device after restoring.
5) Restore your device
We recommend carefully reading Apple's official support documentation on restoring your device before proceeding with a restore. Once the restore has completed you will need to choose to 'Restore your device from a backup' and select the most recent from the list.
Important note: Ensure the restore process has fully completed before removing your device from iTunes or launching Momento. Removing your device too early or launching Momento before Momento data has completing copying may cause issues.
6) Check your data
Once the process is fully complete you should have your data back. If your data hasn't returned this could be due to the process being interrupted or the backup file also containing the corrupt data. If the restore didn't work unfortunately at this point there is no way to recover your data.
Go to iTunes > Preferences > Devices and uncheck the checkbox beside 'Prevent iPods, iPhones and iPads from syncing automatically'. This will allow iTunes to automatically sync your device when connected as normal.
7) Backup your Momento data!
Now you have your precious data back, we highly recommend you make a backup using Momento's Backup Feature.