It has been brought to our attention by one of the users that Kaspersky Total Security Antivirus is severely degrading performance of AmiBroker. This antivirus is so slow that it increases startup time 20 times (from one second to 20 seconds).
It is highly advised NOT to use 3rd party anti-viruses, for performance reasons. Typically anviruses scan ALL opened files non-stop (even if they scanned they one second ago). This is real performance killer if application needs to access lots of data from disk. You need to keep in mind that it takes 10x more time for antivirus to scan the file than AmiBroker to read it, because AmiBroker is hyper-optimized and antiviruses are not.
AmiBroker does not need to "analyze" its files, because it knows the file layout and in fact no conversion of any kind is needed since file on disk has exact same layout as AmiBroker internal data. This can't be said about antivirus.
The best performance is achieved by sticking to Windows Defender (built-in Windows antivirus).
It is also good idea to exclude data files (databases) from scan at all because it makes no sense to scan quotations (they are NOT executables) regardless whenever you use 3rd party antivirus or not.
This is one of many examples where antiviruses made more harm than good. See also: Bad Image (0xC000020) error - McAfee gone mad