Generally, if the menu option to send a file isn't available, this means that the administrator has disabled file transfer capabilities for that user.
If your attempts to upload attachments to a conference or to send files to a contact generate an error message, this means either that the contact that you’re sending the attachment to doesn’t have permission to receive files or that the file type is blocked.
In Skype for Business Online, certain files types are blocked by the Intelligent Instant Message Filter (IIMF) application. IIMF helps protect Skype for Business Online users against the most common forms of viruses without degrading the user experience.
Transferring files to Skype contacts isn't supported.
By default, Skype for Business Online is configured to prevent users from sending files through IM that have the following file name extensions:
.ade, .adp, .app, .asp, .bas, .bat, .cer, .chm, .cmd, .com, .cpl, .crt, .csh, .exe, .fxp, .grp, .hlp, .hta, .inf, .ins, .isp, .its, .js, .jse, .ksh, .lnk, .mad, .maf, .mag, .mam, .maq, .mar, .mas, .mat, .mau, .mav, .maw, .mda, .mdb, .mde, .mdt, .mdw, .mdz, .msc, .msi, .msp, .mst, .ocx, .ops, .pcd, .pif, .pl, .pnp, .prf, .prg, .pst, .reg, .scf, .scr, .sct, .shb, .shs, .tmp, .url, .vb, .vbe, .vbs, .vsd, .vsmacros, .vss, .vst, .vsw, .ws, .wsc, .wsf, .wsh
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