Many Antivirus programs operate constantly in the background checking any files that you work with. This is called "real-time" virus scanning. When you install an AV program, there is a good chance that real-time scanning is enabled automatically.

The trouble with real-time scanning is that you may be "working" with a very large number of files all at once - for example, when you do a data update. In this situation, real-time virus scanning may slow the update enormously, as there are thousands of small files that need to be opened so that the latest data can be appended to each one.

If you find that your data updates are going very slowly, it may be that real-time virus scanning is the cause. If you wish to retain real-time virus scanning, one option you have is to configure your AV program to exclude your data files from real-time scanning.

There are two ways you can do this -

exclude the folder where the data files are kept - e.g. exclude "c:\Trading Data"
exclude the data files themselves irrespective of where they are kept - i.e. exclude *.dat and *.mwd files (all files with these extensions).

Heuristic Virus Detection

Heuristic virus protection involves the antivirus program "guessing" that it has detected malware of some kind (without reference to any known malware signature). We have found that heuristic scan engines can interfere with our program upgrades by intercepting the new program executable as soon as it is downloaded. For instance, Norton Antivirus may report that it has detected and quarantined "Suspicious.Cloud.5" - DataUpdater.exe.

If your Antivirus or Anti-Spyware program quarantines any of our program executables (DataUpdater.exe, DataTools.exe or FX2.exe) please submit the file in question to your security program vendor so that "false positives" may be avoided in the future.