Knowledge Base
Categories: Spam & Deliverability
Blocked Attachment File Types in Business and Enterprise Email
When email attachments fail to send due to security restrictions in your Business or Enterprise Email account. This article explains which file types are blocked.
From a security perspective, the Mail Server will reject inbound mails containing attachments with any of the following file extensions.
| .386 | .fon | .ocx |
| .ade | .fxp | .ops |
| .adp | .hlp | .ov |
| .adt | .hta | .pcd |
| .app | .htr | .pgm |
| .asd | .inf | .pif |
| .asp | .ini | .pl |
| .asx | .inp | .pm |
| .bas | .ins | .prg |
| .bat | .isp | .scr |
| .bin | .jar | .sct |
| .btm | .jse? | .shsb? |
| .cab | .keyreg | .shs? |
| .cbl | .ksh | .slb |
| .cbt | .lib | .smm |
| .cgi | .ink | .swf |
| .com | .mda | .swt |
| .cil | .mdb | .sys |
| .cla(ss)? | .mde | .vbe |
| .cmd | .mdt | .vbs |
| .cpe | .mdw | .vbx |
| .cpl | .mhtm | .vir |
| .crt | .mhtml | .vmx |
| .csc | .msc | .vxd |
| .csh | .msi | .wmd |
| .css | .msp | .wms |
| .cvp | .mst | .wmz |
| .dll | .mp3 | .wsc |
| .dot | .nte | .wsf |
| .drv | .nws | .wsh |
| .exe | .obj | .xms |
To protect you against potential viruses and harmful software, our Mail servers does not 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 .tgz files)
- Documents with malicious macros
- Password-protected archives whose content is an archive
- Note: If you try to attach a document that is too large, your message won't send.
What you can do
If you're sure the file is safe, you can ask the sender to upload the file to Google Drive or ZIP/RAR files and add them as attachments.
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