If you are unable to save or download files in mozilla than-
Clear the download history
Click "Tools -> Downloads -> Clean Up" in the Mozilla Firefox menu. If if clearing the list doesn't help or it causes Firefox to hang or crash (or if the Downloads window is already empty), you will need to manually delete the download history, as follows:
Manually delete download history
1. Exit Mozilla Firefox completely
2. Open the Firefox profile folder.
3. Delete the downloads.rdf file (it will be regenerated when needed).
Prevention
You may be able to prevent this problem by setting Mozilla Firefox not to save a download history:
- Mozilla Firefox 2: Click "Tools -> Options -> Privacy / History" and uncheck "Remember what I've downloaded". (As an alternative, under "Privacy / Private Data" select "Always clear my private data when I close Firefox", then click the "Settings..." button and select "Download History" in the "Clear Private Data" window.)
- Mozilla Firefox 1.5: Click "Tools -> Options -> Privacy -> Download History" and select either "Upon successful download" or "When Firefox exits" from the "Remove files from the Download Manager" drop-down list.