I noticed yesterday that whenever I had Outlook 2010 open on my home PC that my CPU utilization was very high. Outlook appeared to be taking up 50% of my processor. I had no idea why it was doing this, and I wasn’t sure how long it had been doing so. I rarely use Outlook since I manage most of my emails via my smartphone, so it could have been doing this for weeks.
I have Outlook hooked up to my Exchange server (hosted locally), plus a Gmail and a Hotmail account. I checked my Exchange connections to see if there was anything pending, but every connection seemed to be stable. Eventually, I selected “Work Offline”, which had no effect immediately. However, I then closed Outlook and re-opened, and the CPU utilization seemed to be normal. I then unchecked “Work Offline”, and immediately my CPU spiked back up (and stayed there).
Next, I started Outlook in safe mode (by executing “outlook.exe /safe” from the Run prompt). The CPU utilization was fine. I was then convinced that the problem was one of my many Outlook add-ins. I proceeded to move through my list of add-ins, disabling one, restarting Outlook, checking my CPU usage, then disabling the next add-in, and so on. I was worried when I saw there was an add-in referring to Exchange. I was hoping this wasn’t causing the problem, since I need to be able to access my Exchange account. However, this wasn’t the problematic component, and it turns out that add-in is only for Unified Messaging features, anyway (something I don’t use on my Exchange box).
Finally, I came to the Outlook Social Connector add-in. This is the plug-in that allows Facebook, Linked-In, etc. to integrate with Outlook. I was unable to disable the add-in without Outlook locking up (which was awfully suspicious), so to disable it, I exited Outlook, browsed to the file location that Outlook listed for that add-in, then renamed it to .old. For anyone wondering, the location for me was: C:\Program Files (x86)\Microsoft Office\Office14\SOCIALCONNECTOR.DLL. If you’re running the 64-bit version of Outlook, or if you’re NOT running a 64-bit version of Windows, the file location would be: C:\Program Files\Microsoft Office\Office14\SOCIALCONNECTOR.DLL. Once I restarted Outlook my CPU utilization was normal.
Now, the Social Connector isn’t a mandatory part of Outlook for me, but it’s nice to have, so I decided to attempt to fix the issue. First, I went into the Outlook add-ins dialog and removed the add-in. Next, I wanted to re-install the Social Connector, but couldn’t find the installer in Programs and Features. Then I remembered that the RTM version of Office 2010 ships WITH the Connector, so to re-install the add-in, I’d need to run a repair install of Office.
Before running the repair install, I first decided to remove the Facebook, Linked-In and MySpace (not that I use that one anyway; it can stay off) Social Connectors. These are listed individually in Programs and Features (which is Add/Remove Programs, for you Windows XP users). Once I removed those, I then ran a repair install of Office. After that finished, I launched Outlook, checked to see if the Social Connector was enabled (which it was), then exited and installed my Facebook Connector, re-launched Outlook, and voila! Problem solved.
While it may not be entirely necessary to rename the SocialConnector.DLL file .old, I highly recommend it, as the Office repair installation may skip over the file if it detects it’s still there. By renaming it, you’re ensuring you get a fresh copy of the proper file.
TL;DR: Outlook Social Connector was the culprit for high Outlook CPU utilization. Rename the add-in’s DLL file (SocialConnector.DLL) to .OLD, run a repair install of Office, ???, PROFIT!!!