To prevent against potential viruses, Gmail doesn't allow you to attach certain types of files, including:

• Certain file types (listed below), including their compressed form (like .gz or .bz2 files) or when found within archives (like .zip or .tgz files)
• Documents with malicious macros
• Archives whose listed file content is password protected
• Archives whose content includes a password protected archive

Note: If you try to attach a document that is too large, your message won't send. Learn more about attachments and file size limits.

File types you can't include as attachments

.ADE, .ADP, .BAT, .CAB, .CHM, .CMD, .COM, .CPL, .DLL, .DMG, .EXE, .HTA, .INS, .ISP, .JAR, .JS, .JSE, .LIB, .LNK, .MDE, .MSC, .MSI, .MSP, .MST, .NSH .PIF, .SCR, .SCT, .SHB, .SYS, .VB, .VBE, .VBS, .VXD, .WSC, .WSF, .WSH