The model doesn’t have a table named…

I had a similar problem and found the solution.

After an update in our database, I had to rename all my tables from ALL-CAPS to Normal-Caps. So following your example, I changed 'COMPARISON DATA OLD' to 'Comparison Data Old' - and renamed all corresponding query steps, column names etc. When trying to apply the query changes, I got the following error:

The model doesn't have a table named Comparison Data Old 2.

Even though the query didn't mention 'Comparison Data Old 2', and never did. I double checked this by copying the query to Word (or NotePad) and searched ctrl+f. No 'Comparison Data Old 2' ever existed in my entire file. Why it asked for number 2, I never found out, but I did find a solution.

First I added a new table, called 'Comparison Data Old 2'. This resulted in the error message saying:

The model doesn't have a table named Comparison Data Old 2 2.

So that wasn't going to work. The solution, however, was to change the name of the original 'Comparison Data Old' table to 'Comparison Data Old 2'.

This solved the issue and everything worked again - although I had to repeat this step for all other tables. Funnily enough, after applying the query changes I could change the name 'Comparison Data Old 2' back to 'Comparison Data Old' as if nothing ever happened.

Most software doesn't allow for multiple files with the same name, irrespective of caps. So when changing COMPARISON DATA OLD to Comparison Data Old, it might make a copy (number 2) behind the screens. Together with a database update, this might mess things up. But it's only a guess. 

Hope this helps for future troubleshooting!

Joris