I have a WSS 3.0 WFE server running a number of site collections. Recently, I started to have problem when trying to upload files. It is the same kind of problem on different sites.
1). When tried in IE, the error says:
Go back to site
Unable to complete this operation. Please contact your administrator.
Troubleshoot issues with Windows SharePoint Services.
2). I tried open the document library in Windows Explorer, and copy and paste the files over, i got an error with Error 0x80070021. see attached.
3). I tried reboot my laptop, I tried firefox, i tried that email the files to other people, and got the same error.
4). it happens with Word, Excel, Pdf
5). it happens with different document libraries on different site.