After every single update, upon clicking 'Play', the game opens to the login screen, with an Error Message: "There was an error connecting with Maestro. League of Legends will now exit. Please try restarting the client."

The only (temporary)fix is to restart my pc.

Repro steps:
1:Run PBE.
2:Update
3:Click Play
4:Maestro Error.

http://puu.sh/1ZM07

Bump.

having the same problem. it's very annoying. >.> usually I have to restart my computer or repair the files. what seems to be causing it is that sometimes when I start up league, it will act like there's a patch, going over Bin0x0000000 and a bunch of other files, but it's like it's a really small patch, like a few megs. I hope this gets resolved soon. :/

Bump.

Well, did a bit of digging as I've been having the problem myself recently. Turns out, it was directly related to the internet security suite of Avast antivirus. No matter what settings you try giving it, it just doesn't like League and will continue to hate League forever for some reason. Best bet would be to go to the basic free version, or find a better antivirus program.

If you don't have Avast, it may or may not be a similarly mean firewall trying to block out League.

It had stopped for a few days, but it just happened again.

Bump.

usually this is as stated a firewall or internet connection issue.

First you would want to add manual exceptions to whatever firewall and/or antivirus program you are running.
Next would be to try running the client in administrator (Right click the shortcut, select "Run As Administrator").

If that hasn't cleared things up, post back and I'll see what else I can think of; but that should be all you have to do.