After investigating user-reported issues with Exchange Active Sync (EAS) message search we’ve discovered a bug that seems to have been introduced in the iOS11 update (the problem wasn’t present in iOS10 and older versions). It turns out that although the mail app allows selection of three different search filter types : “all fields” (the default); “Sender contains” and “Subject contains”, the search sent to the EAS server is always the same. Presumably this means that filtering of server responses is done on the device to display only those matching the specified search. The problem involves the “Sender contains” search type, as shown in the following screen captures. Here we’d like to search for old messages with “Starmoney” in the subject:

 

 

Click the search button and although a search is submitted to the server, and responses received, the phone displays “No Results Found”!

 

However, if the search is done a second time, results appear!

To be clear: this isn’t a problem with NuevaSync’s EAS service but rather in the iOS EAS client or the iOS Mail App. In fact the screen captures above were done using Office.com’s EAS service just to be sure nothing about our server’s responses was upsetting the device’s message filtering code. Unfortunately until Apple fixes this problem we recommend not using “Subject contains” searches. The default search filter (don’t select either of “Subject contains” or “Sender contains”) will perform a search on the subject.