.Mac causing slow Microsoft Office

I was hoping someone might assist me in fixing a problem I have encountered. Microsoft Word and Excel have been driving me crazy because everytime I try to open a file through the menu (apple-O) it takes forever for the dialog box to come up. It took me a long time to isolate the problem but it appears that having my idisk always on the desktop with automatic or manual syncing is causing the problem. I have the latest update on everything and a very fast ethernet connection at work. I can replicate the problem and get rid of it if I simply turn off my.mac idisk. Anyone have similar problems or know a solution? Thanks.