What OS are you using? Have you recently attached your computer to multiple monitors? I'm just wondering if the extension manager is loading off screen. If you are on a Mac you just need to delete .plist file for the extension and then it should appear back on your primary screen.
Sorry, I should have mentioned my operating system. I'm using Mac OS X 10.6.3 on a 3GHz quad core Mac Pro with 8GB of RAM.
I don't use a second monitor so I don't know how the window could have moved off screen, but I tried using the Gather Windows button in the Displays preference pane just in case it had somehow gotten lost; no joy. It doesn't show up with Expose either, not with F9 or F10. I tried deleting the com.Adobe.ExtensionManager.plist file, but it makes no difference. Interestingly, when I launched ExtensionManager it did not create a new plist file. I replaced the existing plist file with a copy from another user account where ExtensionManager works; this, too, does no good. If I leave ExtensionManager running a few minutes, eventually it shows up in the Force Quit window as "not responding", so it definitely appears to be hanging up at some point. I tried looking at the Console log as I launch EM but I don't see anything that clearly indicates what's happening. It's mostly Greek to me anyway.
I am having this exact problem, where exactly do I find the .plist file on Mac OS X 10.6.5? I would love to get the Extension Manager back onto my main screen since I no longer have the second monitor.
Have you tried deleting your cache file? It solved the same problem for me.
Adobe Community Professional: Dreamweaver
Northern British Columbia Adobe Usergroup: Manager
Thompson Rivers University: Dreamweaver Instructor
My Adobe Blog: http://blog.lawryk.com
The plist file for the Adobe Extension Manager is at /Users/user_name/Library/Preferences/com.adobe.ExtensionManager.plist.
I should add that the particular problem I was having - the Extensions Manager not working - turned out to be a permissions problem. Somehow the permissions on my user folder had gotten mangled, which affected applications that needed to access my user folder in order to function. The solution is somewhat complex so, since that does not seem to be what's bothering you, I won't detail it here unless you let me know you need it.
Thank you so much. There actually wasn't the .plist file that was mentioned here, but what I found was two folders deeper adobe/Extension Manager2/exman_uiPreferences.xml that had the position of the extension manager as <windowPosition_x>-950</windowPosition_x> and when I changed that line of the XML to a positive number my extension manager then opened on my main screen again. Thank you for all your help. The extension manager needs to be closed before the change is made to the XML file as I found out it will rewrite the file with the old numbers if it is already open when you close it.
I saw that XML file, too, while I was rooting around in Adobe related files which, unfortunately, are scattered all over the place. Good job of troubleshooting on your part. This looks to me like a flaw in Adobe's coding, that the window location is not updated when the monitor arrangement changes. Of course, the easiest way to solve the problem would probably have been to connect a second monitor again and drag the window back to the main screen. But you may not have access to another monitor at the moment. In any case, if we can afford the time, trial and error troubleshooting is a good way to learn our way around the system. That was certainly the case with my problem, which actually had nothing to do with Adobe software. I guess I'll never know how my user folder permissions got hosed, but now I know how to fix them if they do - or, rather, I know how to find the article I saved that explained how to fix it.