This is posted for others who come across this thread looking for a solution to the - Validation "Gotcha"
When using VBA to create validation, we can put values in the validation object that we shouldn't - or - leave out an important piece.
Setup: Using VBA, add VALIDATION.TYPE to 3 (xlValidateList) to a cell and either neglect to add a value to FORMULA1 or add a value that is not a comma separated list or a reference to a single column range. Save and close the workbook. When the workbook opens and the worksheet with the improper validation is displayed the workbook will crash. I have replicated this on a few different versions of XL and diffent PCs.
Counter Measure: Assuming you can get the workbook to open, goto VBA and either delete the offending validation:
-or- correct it:
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