Update Mgr update search error for un-installed app

[Antonio Flores]

OS has been LM 17 then upgraded to LM 17.2 on 5 July 2015. On 30 June LM's Update Mgr installed 1 update. On 1 July its shield icon had a red X in it. Details of Error: Downloading updates error for Dropbox from its site even though app wasn't installed. Installed Dropbox via Synaptic. The app worked fine but LM's Updt Mgr continued trying periodically to download updates for Dropbox resulting in the same downloading updates error, then the red X in the shield icon. I un-installed Dropbox via Synaptic. The same error persists to present even though Dropbox is still not installed. I have to turn-off LM's Updt Mgr then permit it to run 2 to 3 times per day for other LM updates. Once the red X is there, LM's Updt Mgr is turned off! (Dropbox was installed until a few months ago. Could there be traces of it somewhere in my sys? Planning to freshly install LM 17.2 OS from new iso.)

[Antonio Flores (anachof)]

Just experienced the Linux Mint 17.2 Update Manager error again. The Updt Mgr box reads as follows: (frowning face icon) then "Could not refresh the list of updates. W:Failed to fetch http://linux.dropbox.com/ubuntu/dists/qiana/binary-i386/Packages 404 Not Found [IP:108.160.172.206 80], E:some index files failed to download. They have ignored, or old ones used instead." Thanks for future assistance. Antonio Flores

[Antonio Flores (anachof)]

New Discovery: If Update Mgr mini-window is left on desktop, updt mgr stops looking for dropbox updates!