Thanks for your advice. There wasn't a $__core.tid file in the tiddlers folder. So in the end I used this recipe!
- I created a new empty server-based wiki - Started the server and opened it in a browser - Installed the non-standard plugins I had in my original wiki - Created a single file wiki from my existing wiki - Dragged that file onto the new empty wiki and imported the tiddlers. Looks to be ok now. -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to tiddlywiki+unsubscr...@googlegroups.com. To post to this group, send email to tiddlywiki@googlegroups.com. Visit this group at https://groups.google.com/group/tiddlywiki. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/d10aba13-58da-4441-bd30-29e127372eee%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.