Solved thanks. I've had a reply from Emsisoft that resolves this. "The files are created during the quarantine re-scan. You can either empty your quarantine in EAM, disable the automatic quarantine re-scan (Settings/General) or exclude a2service.exe from your existing anti-virus software. "
After co-existing happily ESET (v8 Smart Security) has suddenly started to block Emsisoft Anti Malware update files which are similar to this: c:\windows\temp\tmp000049b8\tmp0000040 (the folder and file names change each time). I've set up a wildcard exclusion in NOD32 to no avail and I've submitted some of the update files to you, as well as raising a support request with Emsisoft - but so far no response. Any suggestions please?