I have started upgrading our CAD department from Windows 7 to Windows 10. I have been going directly to feature release 1903. After 2 days, the first person I upgraded informed me that opening a specific spreadsheet in Excel was taking much longer than it had under Windows 7. After investigating I have narrowed the problem down to Windows 10 (1903). The problem does not occur when running under Windows 10 (1809).
The spreadsheet involved contains a good number of pull down lists that lookup people's names in a separate tab. There is a base spreadsheet that contains the framework including a number of tables. The user then fills in the information including selecting names in up to 30 fields. Some users may need to duplicate the original tab that contains the lookup fields. The spreadsheet in question contains an additional 4 tabs. It takes up to 30 seconds to open this spreadsheet. Under Windows 7 it takes about 5 seconds. Delays are also noticeable when switching between tabs within the spreadsheet.
The overall size of each tab is 140 rows by 59 columns, not extremely large.