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Technical Article   FAQ:  Why does the file size increase after saving a map document (.mxd)?

Article ID: 20872
Software:  ArcGIS - ArcEditor 8.3, 8.1, 8.1.2, 8.2, 9.0, 9.1, 9.2, 9.3, 9.3.1 ArcGIS - ArcInfo 8.2, 9.0, 8.0.1, 8.0.2, 8.1, 8.1.2, 8.3, 9.1, 9.2, 9.3, 9.3.1 ArcGIS - ArcView 8.3, 8.1, 8.1.2, 8.2, 9.0, 9.1, 9.2, 9.3, 9.3.1
Platforms: N/A

Question

Why does the file size increase after saving a map document (.mxd)?

Answer

Map documents (.mxd files) are compound files. The information describing the map, layout, and any embedded objects saved in the map is organized into units called storages and streams. When you save a compound file, the streams can become fragmented in a process that is analogous to hard disk fragmentation. This can make the map document larger, though it does not increase the likelihood of the document becoming corrupted. The more times you save a map, the more chance that fragmentation will make the document larger.

Using Save As and selecting a new file name creates a new document with no fragmentation. You can save a fragmented map document as a new document to reduce its file size.

Created: 11/8/2001
Last Modified: 5/3/2011

Article Rating: (2)
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Comments

By brooks_BLM - 05/24/2013 8:40 AM

The article is incorrect or the solution didn’t work.

I agree with Tiffany and think I have seen this problem come up much more frequently when the user is using shapefiles instead of geodatabases in 10.1. I have seen MXDs at 200 mb, which take forever to work with. I advise users to stop using shapefiles and that seems to help their problem.

Rating:

By tiffanypuett - 07/24/2012 8:08 AM

The article needs to be updated.

This is happening at 10.1 on a 64 bit machine. We used the Doc Defrag and then the MXD Dr. This solution works but it's temporary. I've been using Desktop for 10 yrs and never experienced this problem. I consider this a bug. It should be fixed. As a BP, I constantly remind--and is critically important for--users to save the mxd, not only as a bookmark in case it crashes, but to free up the cache (previous ext, next extent, undo, redo, etc). It HAS been my experience that this improves performance and lowers the likelihood of a crash to both save edits and save mxd. I think this should not only be updated to include 10 & 10.1 but also talk about the workarounds and/or suggest a best practice for managing the document. These are working projects NOT JUST MAPS that don't need to be saved alot!!!

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By Anonymous - 11/24/2004 8:45 AM

This method does NOT work if the save as target is the same file name and location as the open document. This becomes a big issue when relative file paths are used