Search emails with attachments in Outlook

I spend absurd time hunting for that email with the file in it. There must be a proper way to search only among messages carrying attachments, ideally by attachment type too.

What is the syntax and what are its limits?

There is a proper way and it stacks nicely. The search box speaks a keyword language and two of its words solve your hunt:

The foundation is hasattachments:yes typed into the search box, which filters the current scope to messages carrying attachments. The same filter lives as the Has Attachments button in the Refine group of the Search ribbon tab that appears when the search box has focus, for the click inclined.

Type targeting uses ext:, as in ext:pdf or ext:xlsx, matching the attachment file extensions. Stack the pieces with the usual criteria into precise hunts: from:priya ext:pdf received:last month finds the PDF Priya sent a few weeks back in one line. An attachment:budget variant matches words in attachment filenames when you remember the name rather than the type.

The limits worth knowing: results depend on the Windows search index, so a rebuilding index returns partial results and very recent mail indexes with a small lag. Scope matters too, the dropdown beside the search box chooses between current folder, current mailbox and all mailboxes. A hunt that comes up empty is usually scoped one level too narrow. Attachment contents are indexed for common formats, meaning search also reaches words inside the attached documents themselves, powerful once you know it is happening.

from: plus ext:xlsx found in four seconds a spreadsheet I once spent twenty minutes scrolling for. The contents indexing explains several search results that used to seem like magic.