Tree corrupt: "Can't get useful data"

[onkq]

My mom added people to the tree. Somehow she was not able to open the tree anymore, with the only error message: "Can't get useful data"

Unlike #121, I can see how many people & generations I have. But I'm unable to open it. I would really love for someone to help me solve this, as it's alot of people.

[jer194]

Hard to tell what's wrong (maybe Michele knows).

I would check here (if rooted, or via recovery):
/data/data/app.familygem/files/*.json

This should contain your complete trees in json format.

I'd assume not all individuals have been added using FamilyGem, rather imported from somewhere?
Also, 56 generations, that's more than 1000 years? That's far back :-)

[onkq]

I will check this and update. Yes my mom has added each and every person using FamilyGem, We are further down than 1000. Even met some kings in our family tree

[jer194]

Or, if the 3 dots at the right side still work, you might be able to at least retrieve a backup (as zip, or gedcom) ...

[michelesalvador]

Persons & generations numbers are not significant in this case.
Unfortunately that "Can't get useful data" message means that the tree's JSON file is irreparably damaged, probably completely empty.

You can check the content of the tree JSON file activating the advanced tools, then from the tree three dots menu ⋮ → Save ZIP backup.
The exported ZIP file contains tree.json, which is an exact copy of /data/data/app.familygem/files/1.json (your tree).

You can recover your tree if:

• Had previously made a ZIP backup
• Shared the tree less than a month ago
• Exported a GEDCOM file

Another possibility is to use Google Drive's automatic backup.
If it was activated, you can uninstall Family Gem and reinstall it from the Play Store: you should immediately see the tree restored from backup.