Data validation arrows flash and disappear for one user

[Asbestos_Jen]

My spreadsheet was created in Excel 2007. There are data validations in a few places, all referring to named ranges on another sheet in the same workbook. The drop-down arrows are missing only for one user, who has Excel 2010. Other users have 2007, 2010, or 2013. The dropdowns were working prior to having a validation with "indirect" referring to linked pictures of named cells (pick report approver from dropdown, and appropriate signature appears on final report), as shown here: https://www.extendoffice.com/documents/excel/2098-excel-drop-down-list-with-images.html.

Because this is happening only with one user I assume it is something to do with her system or excel settings. Users OS varied, with Win7 and Win10. The problem PC and I are both on Win7. I have been googling for days, and have tried the following with no change:

+ changed the "show/hide objects" setting on the other users' computers (box checked/unchecked/checked).
+ saved the file as .xlsx (original) and .xlsm (though there are no macros in the workbook)
+ saved the file as .xls (broke lots of formulas, but didn't fix anything)

Any thoughts?

 

[mole999]

what do they have in their xlstart / any non standard add ins

 

[Asbestos_Jen]

There are no add-ins, and I can't access her xlstart.