I'm working on a site that uses several contact subtypes for the Organisation contact type. Following a recent upgrade, everything seems to be working fine, but a basic or advanced search for contacts of this particular subtype gives zero results. Searches for other contact subtypes are working fine. Looking at the database I can see that there are in excess of 1300 contact records with this contact subtype, and they aren't in the trash.
Any thoughts on what the issue might be, how to fix it, or how to work around it (I was thinking about the possibility of creating a new contact subtype and applying this to all of the records - assuming of course that I can find them!).