We ran into a situation where Vista clients with Excel 2007 were slow in open and saving of files.
We came across the following which has helped the situation
We checked the “Lookup wizard” Add-Ins in Excel Options Add-Ins this made excel faster in most areas.
We tried removing the addins, and we kept on getting this error. “The connected state of Office Add-Ins registered in HKEY_LOCAL_MACHINE cannot be changed”
We found that the only way to disable the addins is by opening the office program using the “Run as Administrator”
We could then uncheck or delete the add-ins
This did fix the issue.
