To be honest, I did figure out the issue - or at least I think I did. Basically the tags it refers to are the ones you add followed by a comma. I did at least 5 of them (i.e. Excel, Date, Formula, VLookup, VBA Code,
...and then the error disappeared so it was to do with those tags.
Originally I thought perhaps it was something within the main body of the message but it appeared to concern the tags you add below the main message.
Thanks. I'll have to study that. I never modify those options ("user tag list" and "tags for this thread"). So it is unclear why I get an error only sometimes.
I'm not aware of doing anything differently, other than occassionally adding more than one table. But IIRC, I get the "tags exceeded" error sometimes when I add just one table.
Typically, when I add a table, I also add code-tagged text, which I use to list the formulas. And typically, I "reply with quote", creating a user or thread tag (?). Arguably, that's 3 tags; and when I click "add/edit tags", it says I can add 2 tags "to this thread". Not sure if that means 2 additional tags or 2 tags totals.
Anyway, my point is: since I don't do anything differently (IIRC; TBD), I don't understand why I get the error only sometimes. The operative word is "differently". I'll experiment to see if that's really correct.
Thanks for your thoughts. Glad that you solved your problem.