While scanning your computer with mcafee it may seem to stop responding while a large file is scanned and this happens in scenarios where it encounters a large compressed file for eg. .zip,.rar .And also for your information , VirusScan scans the contents of compressed files, it must temporarily decompress the contents before they can be scanned.
Since File decompression is a lengthy process, particuarly on older computers with minimal amounts of RAM and slower processors. Additionally, VirusScan requires time to scan each individual file contained in the compressed file. When a file requires decompression, scanning can take longer to complete.
note : moving thread to virus scan discussions
yes I see McAfee scans compressed (.zip, .rar, etc.) files, but how does it understand if a file is compressed when it doesn't have one of those "standard" filename extensions. For example, a .exe file could be a self-extracting zipped, or an installer file, which includes compressed content but it hasn't a .zip filename. Will the scan work in those cases too? And what if I intentionally change the file extention of a .zip to a non standard one (i.e. .zap)?