I have the similar problem with ProSeries 2018 and 2019 in Jan. 2021. Every time I efiled a business client, the program stop working. I have to close it and reopen the program for efiling next client. This problem started three weeks ago or after installed ProSeries 2020 on my computer. I tried on another computer, it has the same problem. Contacted Intuit support but didn't solve the issue.