You are using this over a LAN, and not WAN, Cloud/One Drive or WiFi, yes? If LAN, Ajax is possibly correct.
Maybe
- too many records are being loaded into forms as opposed to queries that filter accordingly
- there are too many calculations, subqueries involved at times
- lack of indexing
- long text (memo) fields being mined for data
etc
Some of these things could come in to play even if user doesn't open a form. The fact that you can only regain speed by closing Access suggests some of the above. Are the BE tables Access or something else, or are connections to external sources being made in code?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.