I have a issue with identical queries: One is slow and the other is fast. My problem was discussed in another forum (https://social.msdn.microsoft.com/Forums/office/en-US/38ce261b-f128-4e6c-b359-9301f993abb1/identical-queries-one-is-fast-the-other-slow?forum=accessdev), but I did not get a real answer, just a way to circumvent the problem. The sloooow query could be made fast (I found out) e.g. by changing the name of one of the tables that are referenced by the query!
This is not very satisfactory because from now on, whenever I have a query that does not respond in a second I'll be suspicious that I again have met the problem and perhaps could drastically improve the query by making some random/unknown change.
For more information on the problem, follow the above link.
In the other forum I hoped that someone from Microsoft would have taken responsibility of the problem that I tend to call an error in Access - of course they have to be aware of the problem. Therefore, I try to reach out for Microsoft in this forum, too.
Best regards,
Helge