A client is running Office 2007 SP2 on Vista Pro x64.
He has an Exchange and a POP account. Cached exchange mode is disabled due to the large mailbox size.
After approximately 30 minutes of use, Outlook no longer allows him to forward messages with attachments. When these messages are opened, the attachments cannot be opened, but they can be viewed (in the case of images like PNG and JPEG files) if he manually right-clicks on an attachment in Outlook and clicks on "Preview". If he attempts to forward/reply the message, or open an attachment by double-clicking, he receives the following error message:
"Changes to the item were lost due to a reconnect with the server".
The only temporary solution is to close the Outlook client and reboot the machine.