What email attachment file types are prohibited?

ade adp app asd asf asx bas bat chm cmd com cpl
crt dll exe fxp hlp hta hto inf ini ins isp jse lib lnk mdb
mde msc msi msp mst ocx pcd pif prg rar reg scr sct sh
shb shs sys url vb vbe vbs vcs vxd wmd wms wmz
wsc wsf wsh

Microsoft recommends we block this list of extensions. Email containing these attachments is automatically deleted and there is no way to recover it. If you need to send or receive one of these file types, please see the Answers article on Sending Prohibited Attachments.