When you open a file and it shows “Not a valid XMind file”, please note that your file may be corrupted. At this time, please send us feedback from XMind for iOS.
Here you can send us feedback.
Please tell us the following information when you send the feedback.
1. Where did you create the file? On XMind for Android, XMind: ZEN or XMind 8?
2. Before the file corrupted, what did you do with the file?
3. Please send us the file and we will try to fix the file for you. Please note that if the file become 0KB, we are unable to recover it any more.