What does "backend warning" mean? I've googled and searched but haven't found where anyone else has asked this question, much less an answer.

Explanation would be much appreciated.

Backend for what? Client and server relationships are typically referred to as "frontend" and "backend". The frontend is usually the user interface. The backend is the actual server/database/whatever. The frontend software may reside on the same machine as the backend (like on a TiVo) or might be on a different machine (think a graphical interface to a huge payroll database).

So chances are there is some minor problem or potential problem on some backend (i.e. server) on your machine. It could be something like the backend isn't started or you're running out of space or something else.

Can you post the actual message?

Actually my question originates, as it were, in another forum. Here's an excerpt:

". . .Well today, software update notified me that: "21 new updates and 9862 new packages are available for your system (as of update check performed Friday Dec. 18, at 10:51 AM)."

"Is that 9,xxx as in THOUSAND?

"After I clicked "yes" for the updates -- (I've learned to carefully scrutinize what all synaptic does as it's been known to remove itself along with hundreds of other packages) -- I'm still getting an update notification for the same 21 new updates.

"Only since beginning this post has software manager alerted me to six new messages, all the same: "Backend warning." And the synaptic icon has a yellow, triangular, icon with an exclamation point superimposed on it.

"What do I need to do? I promise that while you're reading this, I'll be searching and/or googling "Backend warning," as I have only the vaguest idea of what that might mean."
* * * * *
Everything else was answered and all is well; however, I wasn't told what "Backend warning" means. I guess it was assumed that I'd find out on my own as indicated. Problem is, however, I've found no specific answer -- and, no, not searching this forum either.

I'm sure that my then-immediate concern about it is now moot. Nevertheless, just for my own personal knowledge base, I still want to know.

As always, any help will be much appreciated. Thank you.

Is there anything in your system log files that indicate a problem? Try reading through the output of dmesg or through the /var/log/syslog file.