I support some tax consultants who love to use Excel when they should probably be using Access. Anyway, they have created two Excel files, A and B. File B has cells linked to file A. File A is 27 MB and file B is 16 MB. One worksheet has roughly 1 million rows and there is another worksheet doing a whole bunch of SUMIF on the 1 million rows. Not the best idea, but whatever.

Both Excel files open and recalculate within a reasonable amount of time (1-2 minutes). For a files that large, this is acceptable.

Here is the problem: Once you change a cell, and save the file B, it takes a solid 30 minutes to save the file, and the processors are going full speed. I've tried this on 6 different machines, all running Windows XP SP3 with Office 2007 SP2 and all patches. The specs vary from one machine with 512 MB or RAM to a machine with 4 GB of RAM and quad processors. Same result every time.

Here is the clincher: If I do this same save operation on a VMWare virtual machine, the file gets saved in 1 minute. I've tried this with my ESX servers at the office, my Mac Fusion at home, and VMWare workstation at the office. It does not matter how much RAM the virtual machine has... it saves in about 1 minute every time.

Does anybody have any idea why this is happening and how to fix?