when importing a vB4 forum and you have two users with almost the same name like for example:
where the only difference in the name is the german umlaut ü, the user will be merged into the user without the umlaut.
old vB4 forum:
new xenForo forum after import:
The user MüMa is not existing any more after the import. We`ll have to re-create those users and manually re-assign their postings to those users.