Thunderbird has three methods to search. Global Search, Quick Filter search and 'Search Messages'. Each method provides variants on type of search.

You need to use: Either via Menu Bar: 'Edit' > 'Find' > 'Search Messages' OR via 'Menu app icon' : 'Tools' > 'Search Messages' Or use shortcut keys : 'Ctrl+Shift+F'

This works similar to 'Message Filters' IF you want it to match ALL conditions : 'Match all of the following' IF you want it to match ANY of the following : 'Match any of the following' Please note: From, To, Cc, Bcc may not necessarilly match a 'Reply-to', so if a 'Reply-to' may be different then choose the 'Any' option.

You can use ' From, To, Cc, Bcc' contains and type email address Then add another condition: 'Age in days' - 'Is less than' and type 30 Add another condition: 'Reply to' Click on 'Search'

@Toad-hall, This doesn't help because if I do You can use ' From, To, Cc, Bcc' contains and type email address Then add another condition: 'Age in days' - 'Is less than' and type 30 Add another condition: 'Reply to'

then surely if From/to and Reply-to are different, I need to do ANY to get both addresses, but if I add in Less than 30 to the ANY, then I'm going to get every single email less than 30 days - isn't that so?

I'm not aware of any way to combine To, From,... and Reply-to in a single rule, or to combine an OR rule with an AND rule in a single filter, even with an add-on like Expression (Power) Message Search - NG. I think the best you can do is to set up a search as in the attached picture, then click the Date button in the results pane to narrow them to the desired date range. Note that Reply-to is added as a custom header. Or, make a filter to copy messages with Age < 30 to a folder, then run the search there.