Search inside attachments and across multiple PDF files

The word you remember may sit inside an email attachment, or in one PDF among hundreds in a folder. Outlook, Windows and Adobe Acrobat Reader can each search the text of documents, each in its own place. The steps below follow each maker's documentation.

Search inside attachments in Outlook

Classic Outlook

For the mail synced to your PC, classic Outlook searches through the Windows search index; with a Microsoft 365 or Exchange account it can also search on the server. With Instant Search enabled, a search can also match text inside attachments, not only in the messages.

To list only messages with attachments, type hasattachments:yes in the Search box, or select Has Attachments.

If results remain incomplete on a PC with a PDF program installed, Microsoft documents a possible cause: a PDF iFilter can stall the Windows search indexer, so that Outlook items are indexed repeatedly. Update the applications that offer PDF functionality, then rebuild the index as described in Outlook search not finding emails.

New Outlook

Type a keyword, such as the name of the person who sent the attachment or a word describing the email or file, then select Files to narrow the search. The filter button on the right of the search box opens Advanced Search, where the Attachments box shows only messages with attachments.

Search file contents in File Explorer

Windows keeps an index of the words and metadata in your files. A fully built index can return results in a fraction of a second, where a search without it can take minutes. Two settings decide which folders are in the index, and whether the text of a file type is.

Which folders are indexed

In Windows 11, open Settings → Privacy & security → Searching Windows (called Search in some versions). Under Find my files, Classic indexes your Documents, Pictures and Music folders and the desktop by default; Enhanced indexes your entire PC, except the folders you exclude. To add a folder, select Customize search locations, then Modify.

Whether the text of a file is indexed

1. Open Indexing Options from Control Panel and select Advanced.
2. On the File Types tab, select the extension, for example pdf or docx.
3. Under How should this file be indexed?, choose Index Properties and File Contents. Select OK, then Close.

With properties only, a file is found by its name but not by its contents. The first indexing can take several hours, depending on the amount of data; after that, Windows indexes changes in the background. Then open the folder in File Explorer and type the word in the search box.

Folders on a file server

Microsoft documents two ways for a network folder to be in the index: the share is indexed on the server itself, or the folder is made Always available offline. That option “creates a local copy of the folder's files, adds those files to the index, and keeps the local and remote copies in sync”.

Search a folder of PDFs in Acrobat Reader

Acrobat Reader can search all PDF files in a selected folder:

1. Open Advanced Search: in the new interface, press Ctrl+F, select the ellipsis (…) on the Find toolbar and choose Advanced Search; in the classic interface, choose Edit → Advanced Search, or press Shift+Ctrl+F.
2. Select All PDF Documents In, then choose Browse For Location in the menu below it.
3. Select the folder, on your computer or on a network, and click OK.
4. Type the word or phrase and start the search.

Encrypted PDFs usually have to be opened and searched one at a time. The search covers the PDF documents in the folder; for Word and Excel files, use File Explorer.

One search across attachments, OneDrive, SharePoint and server folders

The methods above search mail and attachments in Outlook, files in File Explorer and PDF files in Acrobat Reader. SearchFlow, a Windows application by DomusFlow BV, puts one search field over your mail and documents and keeps its index on your PC. It searches:

• the text of PDF, Word, Excel and PowerPoint files attached to your emails, not only their names;
• the documents in your OneDrive, including the text of PDF and Office files;
• the document libraries of the SharePoint team sites you have access to;
• the folders you add in Settings, on a file server by drive letter or network path, or on your PC, including the text of their PDF and Office files.

Results appear while you type. A match inside an attachment brings up the email it arrived with, with the attachment's name highlighted; one click opens the document. Documents open in their own program.

Scanned documents without a text layer are found by their file name only, as are images, archives, drawings and older Office formats such as .doc and .xls.

SearchFlow works with Microsoft 365 work or school accounts. An administrator of your organisation approves SearchFlow once; after that each employee signs in with a work account.