please post value list definition for the dropdown.
When you create a clone of the database your global variables lose their values.
My guess is that you have a relationship that has a global variable in it, and that your value list depends on that relationship or a calculation used in the import process requires it to have a value.
When you find that global variable add the initialisation of that variable to your on-open script so that it always has the desired value.
If your value lists were based on values in a field instead of static, hand entered values, they are gone when you clone
The dropdowns have custom values. Easiest way to describe what I'm doing is each image shows (say) forty items, each of which have to be evaluated on two different scales (call them Smith scale and Jones scale, Smith having twenty stages and Jones having five). So Image One, Item One might be Smith 16, Jones 3. Image One, Item Two might be Smith 15, Jones 2, and the like.
I think the problem may not be with the dropdowns value list but with the table to which they refer (call it Smith.Experimental::ItemOne.Smith). That table has a relationship with the table I import, and the relationship is based on each record's identifying number. The previous dataset had completely different identifying numbers, so I think I need to create a new table, import data, and remake the new relationship. I'll give that a try and see if it works.
I checked and as far as I can tell I do not have any global variables. I think it is a reference problem -- the dropdowns store the information entered in a table, which relates to the imported data by reference number. But the numbers in that table will all refer to the refence numbers from my first dataset, so the relationship is borked. Will see if this theory works out.
They were hand-entered, but the suggestions here have nudged me in the direction of a relationships problem. Thanks!
Solution: it was a relationships-related problem (the corresponding identification numbers were not in the related table). I imported the new information to the appropriate tables and the drop-downs work again.
I was not able to figure out the problem with the image files, but because they worked when imported into a copy, rather than a clone of the previous database, I made a copy, deleted all records, and imported the new ones. My database works. Thanks for the suggestions -- they got me on the right track.