Sophos 8.0.1c - cannot enable on-access scan

Same here. I installed Sophos 8.0.1c a few days ago, and everything worked fine. Since today, the shield remains grey, the on access settings tab shows it's disabled and the button to enable it is disabled and shows the label "Scan anhalten" (stop scan in german). A few minutes after login a popup shows up that tells me the Anti-Virus process is not running. Any ideas how to fix this?

I have the same problem.  Directions say to "click on scan files" in preferences but I cannot find that option on the page that shows the on-access status - a red dot for OFF in my case.  Removed Sophos and reinstalled but the  problem remains.  Install in both cases was successful.

I have the same problem. I imagine we have to wait for a new version that corrects this error.

I am having the same problem as well and have tried uninstalling/reinstalling and manually deleting the preference file and I've had no luck. It seems to be a  bug in the newest version of the software. That there are already a group of users who are having this problem most likely means that this isn't a user problem, so we'll have to wait for a bug-fix from the developers.

So far, I've been generally happy with the response time from Sophos when there is a problem with the home (free) version of the software. There are other companies who all but ignore users of their free products, so the assistance Sophos has provided is much appreciated.

Before I removed Sophos, I ran Lion Disk Utility, verified and fixed a couple of minor errors and repaired some permissions.  A second verify found no problems. I went into finder and opened the program.  This time I was able to start a local scan but it seemed slow and hung up after about 50% of the files.  I couldn't take the pinwheels and deleted the program again.  I'm with everyone else hoping that Sophos finds a fix.  FWIW, I'm running a late 2010 MBP with Lion 10.7.3 on 2 GB of ram. 

Lion is supposed to run on 2 GB from what I read but I wonder is that is part of the problem???

Update to my 4/18 message.  After reading more about Sophos 8.0.1c and Lion, I downloaded Sophos 7.3.  The install and local disk scan went well and it appears I am running Sophos 7.3 successfully.  I hope it is close to being as robust as version 8 but I feel 7.3 is better than no protection; until the fix for version 8.0.1c is released.  It has been running about 4 hours, so far so good.

I have had all the same problems listed here by everyone else. It makes me lose hope that it could possibly be made to work until the next verison comes out.

Ok, here is what you do:

First, go into Control Panel, User Accounts, Change Account type. Then, highlight your user and click properties. Then go to the tab which says "Groups", then add your self to the group "SophosAdministrators" (From the "Other" dropdown menu. Then click "OK". Now go to Sophos and click configure and it will not be greyed anymore.

Hope this helped! :D 

We are using Mac's so there is no Control Panel so no tab which says "Groups"!

Are you using an administrator account or a user account?  It sounds like you've got a user account and the file permissions somehow got set incorrectly during the update (upgrading via the user account instead of an admin account maybe?).