Outlook 2000 error this item could not be saved to this folder

I have seen multiple times where doing an Office upgrade corrupts with Outlook profile. Outlook profiles (when using them) can cause strange error messages and such. I would create a new Outlook profile for the user and see if it corrects the issue.

Also, another thing I have seen is when performing an upgrade sometimes Outlook will (somehow) get installed and still have the old version on the same machine. Typically you can do paralle installs with the exception of Outlook.

Sometimes in the migration proess it will fail and 2 copys of Outlook will reside on the same machine. In this case I would just uninstall all versions and install the version you wish to use.

Hope this helps

Check these:
https://www.experts-exchange.com/questions/20062467/MS-Outlook-Item-could-not-be-saved.html

https://www.experts-exchange.com/questions/20465737/The-item-could-not-be-saved-because-it-has-been-changed-by-another-user.html

I have removed all version and installed the 07 version. Now when I connect to Exchange through Outlook, there are all the inbox folders, but nothing in the folders after it creates the local copy of the mail box. I login into OWA and all the folders are there. I removed the account and re-added the account with the same problem. When I try to create a new email there is also no send button.