can someone help me with the criteria of a search that gives me a list of customers with no transactions for a particular time period - example: all customers who didnt buy last November.

I'm sure there are options here, but my first thought was a customer summary search where you show the transaction fields.document number in the results and group on the customer, count the document column. A filter of the transactionfields.date You can add a summary criterea where the count of this field = 0

(Deleted my answer, you've explained it better, and count is a better option than sum of amount in case there are netting transactions)

lol, while I agree, your answer would definitely find 0s!

what am i doing wrong here because im getting 0 results -

If you remove the summary criteria, do you get results?

if i change summary criteria to 1 instead of 0, i get accurate results

what if you remove it? do you get results that show count of 0

no

so you're only issue is the summay criteria. Make it look like this instead