Game System Conversion - Tag cannot be deleted

[Merion]

I finally tried to convert my legacy realm to pathfinder.

I made a copy of my realm and hit the convert button. Unfortunately somewhere near the end, RW crashes with the "Tag cannot be deleted" message in the crash report. I've sent the report, but wanted to ask here too, if this is a common problem and if there is a way to find out which tag is the culprit, so I can delete it before conversion.

I hardly ever use tags at all, but I did create some tags in the early days, when places could not yet be tagged as river, mountains or such. I thought I removed the manually created ones by now, but I suspect this might be a reason for the crash.