Unclean removal of Eset Mail Security from SBS 2008
Had a Server 2008 box that originally had EMSX 2.7 installed, which was replaced with EMSX 4.
The AV went corrupt and wouldnt uninstall so a forced removal with the ESET utility was used. This left a remnant in the Exchange Transport Agent service which caused Exchange to lock off mail receipt.
To remove the remnant you have to edit the config file below.
C:Program FilesMicrosoftExchange ServerTransport RolesSharedagents.config
Edit in notepad and remove the top line that mentions the ESET agent.
The transport agent should start now and mail will flow.