Apologies to the original author, I’ve found this post a 1/2 dozen times, all with the same text, so I guess I’m copying an existing copy and paste.  But, this was worthy of placement here as I ran into this again today…

By default, SharePoint Search Services can crawl and filter a file with a size of up to 16 megabytes (MB). It will always crawl the first 16MB of a file. After this limit is reached, SharePoint enters a warning in the gatherer log “The file reached the maximum download limit. Check that the full text of the document can be meaningfully crawled.”

How to increase the limit beyond 16MB

To increase the limit of 16 MB, you must add in the registry new entry MaxDownloadSize.  To do this, follow these steps:

1. Start Registry Editor (Regedit.exe).
2. Locate the following key in the registry:
3. HKEY_LOCAL_MACHINESOFTWAREMicrosoftOffice Server12.0SearchGlobalGathering Manager
4. Open Edit – New – DWORD Value. Name it MaxDownloadSize.
5. Double-click, change the value to Decimal, and type the maximum size (in MB) for files that the gatherer downloads.
6. Restart the server.
7. Start Full Crawl.

NOTE: Increasing the file size may cause a timeout exception because the crawler can timeout if the file takes too long to crawl/index (because of its size). To increase timeout value, follow these steps:

How to increase the timeout value

1. In Central Administration, on the Application Management tab, in the Search section, click Manage search service.
2. On the Manage Search Service page, in the Farm-Level Search Settings section, click Farm-level search settings.
3. In the Timeout Settings section change Connection and Request acknowledgement time.