MS Excel files open extremely slow over the network

A customer recently complained that opening Excel 2003 files over the network drive was very slow and seemed to cause Excel to hang. If you took that same Excel file from the network drive and copied it to the local computer drive the slowness went away.

A search for this type of problem revealed a lot of different answers, however here’s the solution that worked for this customer:

• Remove the 4/07/2011 Excel security update KB2541025.

I tried other resolutions offered, however this was the one that resolved the slowness for me (other solutions are offered below). It seems Microsoft has introduced some security checks regarding remote code execution that breaks or severely slows down opening files over the network. No doubt an update will follow but it is not available as of this writing.

[Update: I had another XP computer that I also had to additionally uninstall the KB2502786 update]

How to remove this Excel Security Update:

To remove this update from within Microsoft Windows XP, go to Add/Remove Programs and click the checkbox at the top of the window to Show Updates. Now scroll down until you see the KB number shown above and uninstall it. I reboot the customer’s computer afterwards just to be sure there’s no residual information in the Windows Registry.

After removing this update Excel was again able to open files over the network.

Note: Be careful that this update does not get pulled again on the next Windows Update sequence.

Other things to try:
One of the comments below also suggests: http://support.microsoft.com/kb/2570623, option 4

– Microsoft Support
– Check your DDE
– Check the comments below.
– Thanks to Steve Harman over at Techarena for offering this fix!