http://www.sophos.com/en-us/support/knowledgebase/35340.aspx
Third-party software is not installed
If third-party security software is not listed in Add/Remove Programs (Programs and Features for Vista+) then the CRT is most likely detecting a leftover component or fragment of the previously installed software.
Check in the AVRemove.log for what item is causing the detection. Open the log with a text editor and search the log from the bottom upwards for the string Info: Removing detected products and check what items are mentioned immediately beneath that text.