Taskbar does not Auto-hide all the time Windows 7

For me the problem seems to be caused by the USB safely remove hardware notification when I plug in a device but it is intermittent. Sometimes it doesn't stick at all, sometimes it sticks until I close the autoplay window (But the autoplay window is often buried with no indication that it requires my attention), sometimes sticks until I click on then off the usb notification icon and sometimes until I eject the device.

This is clearly an issue that many people are experiencing. I hope that MS are taking these comments on board and not just sticking their heads in the sand. I keep hoping that the next update will sort it...

What I have found was my current issue was the Outlook icon in the hidden icons . I simply right-clicked on the icon and selected "Hide when Minimized" and my taskbar hid again like it's supposed to! I'm not sure if this will adversely affect my Outlook reminders in any way, but after searching for this for what seems like forever I am happy to say that it worked for me...this time.

I sometimes get the exact same problem, and I was intermittently getting it for years with XP prior to updating to Win 7, and I seem to remember getting it in 95/98 as well.  In any case, it's most definitely not a new issue in Windows.  More like one of the "classics."

I just noticed that it happens on my Windows 7 install when I disable Avast's shields so that I can play a game without anti-virus running in the background and slowing things down.  Once Avast is in "disabled" mode, you simply cannot hide the taskbar no matter what you do.  As soon as you re-enable Avast's realtime shields, the taskbar immediately cooperates again and automatically disappears.  That could be a potential solution for some out there -- when it happens again, try toggling settings on any apps that reside in the systray (or just exiting those apps) to see if the problem goes away.  There are other times when that is NOT the issue, though, and I'm still at a loss on a fix for those occurrences.

The Taskbar Slapper program someone linked in this thread does absolutely nothing for me on Win 7 x64 as far as I can tell.  It briefly appears in the systray area, but there are no tooltips and it poofs as soon as you point at it (meaning the program was already terminated and left a ghost icon behind in the systray).  Has no discernible effect on my taskbar autohide problems, though.

As far as the suggestion about "lock the taskbar" having anything at all to do with this problem, that's a typically clueless MS support answer.  While I admittedly have tried fiddling with that setting on more than one occasion over the years to try and fix the problem (my taskbar otherwise remains locked), I have never seen it have any effect whatsoever on the taskbar autohide feature, nor would I seriously expect it to have any effect since it's completely unrelated to that feature.  Aren't you MS people at all embarrassed to be giving completely useless, non-relevant and unhelpful answers like that?