What is the difference between a Threema ID and an ID export?
To restore a Threema ID, you need an ID export (or a Threema Safe backup). It consists of 80 digits and letters in groups of four characters (separated with dashes). You string is shown in two ways when exporting an ID: as plain text for copying/pasting and as a QR code.
In the restore menu, you can either enter the long string manually, or you can scan the QR code. Restoration is only possible with an ID export. If you mistakenly scan a public Threema ID, you will see a long string after scanning that starts with “3mid:”. Restoration will not be successful in that case. Please ensure that you are using an ID export for restoration.