Update 2019-10-22

Added .pyz & .war

Update 2019-09-08

Added large list of audio and video extensions.

Update 2019-05-19

Added .nst to email file extensions

Update 2019-04-28

Added more file types to block that are related to Total Commander plug-ins (the .lng and .mnu file extensions are not included though). More details in this article.

Update 2019-04-27

Added .wcx — Total Commander Plug-ins with auto-install capability (GUI is shown, but always).

Update 2019-03-24

Added Additional Archives file Extensions controlled by WinRar and WinZip (after their install)

Old Post

There are many lists like this floating online, so I thought I will create one more 🙂

I took Registry hives from a couple of systems, extracted the file extensions and their associations and came up with this list.

This is v0.1. I will update it with time.

• Access
  • .accda, .accdb, .accdc, .accde, .accdr, .accdt, .accdu, .accdw, .accessor, .accft, .adcf, .ade, .adn, .adp, .frg, .laccdb, .ldb, .mad, .maf, .mag, .mam, .maq, .mar, .mas, .mat, .mau, .mav, .maw, .mda, .mdb, .mdbhtml, .mde, .mdn, .mdt, .mdw, .mdz, .snp, .wizhtml
• Excel
  • .csv, .slk, .xla, .xlam, .xlk, .xll, .xlm, .xls, .xlsb, .xlshtml, .xlsm, .xlsmhtml, .xlsx, .xlt, .xlthtml, .xltm, .xltx, .xlw, .xlxml, .ods, .xld, .csv, .dif, .xlb, .xlc, .xlt, .xlv
• Word
  • .doc, .dochtml, .docm, .docmhtml, .docx, .docxml, .dot, .dothtml, .dotm, .dotx, .odt, .rtf, .wbk, .wiz, .wll
• Powerpoint
  • .odp, .pot, .pothtml, .potm, .potx, .ppa, .ppam, .pps, .ppsm, .ppsx, .ppt, .ppthtml, .pptm, .pptmhtml, .pptxml, .pwz, .sldm, .sldx
• Outlook
  • .det, .eml, .fav, .fdm, .hol, .ibc, .msg, .nk2, .nst, .ofs, .oft, .ost, .otm, .pab, .pst, .vcs
• Visio
  • .vdw, .vdx, .vsd, .vsdm, .vsdx, .vss, .vssm, .vssx, .vst, .vstm, .vstx, .vsx, .vtx
• Publisher
  • .pub, .pubhtml, .pubmhtml
• InfoPath
  • .infopathxml, .xsf, .xsn
• OneNote
  • .one, .onepkg, .onetoc, .onetoc2, .ms-one-stub
• Office Theme
  • .thmx
• PDF
  • .pdf
• Powershell
  • .cdxml, .ps1, .ps1xml, .psc1, .psd1, .psm1, .pssc
• Audio
  • .3ga, .aac, .ac3, .adt, .adts, .aif, .aifc, .aiff, .alac, .amr, .aob, .ape, .apl, .au, .caf, .cda, .dts, .ec3, .flac, .it, .lpcm, .m3u, .m4a, .m4b, .m4p, .mid, .midi, .mka, .mlp, .mo3, .mp2, .mp3, .mpa, .mpc, .mpl, .mtm, .ofr, .ofs, .oga, .ogg, .opus, .ra, .ram, .rec, .rmi, .rmm, .rnx, .rp, .rpm, .s3m, .snd, .spx, .tak, .tta, .umx, .wav, .wax, .weba, .wma, .wpl, .wv, .xm
• Video
  • .3g2, .3gp, .3gp2, .3gpp, .amv, .asf, .asx, .avi, .avs, .bdmv, .divx, .dtcp-ip, .dv, .DVR, .dvr-ms, .evo, .f4v, .flv, .hdmov, .ifo, .IVF, .k3g, .m1v, .m2p, .m2t, .m2ts, .m2v, .m4v, .mk3d, .mkv, .mod, .mov, .mp2, .mp2v, .mp4, .mp4v, .mpa, .mpe, .mpeg, .mpg, .mpls, .mpv2, .mpv4, .mqv, .mts, .mxf, .ogg, .ogm, .ogv, .pmp, .qt, .ram, .rec, .rm, .rmvb, .rv, .tod, .tp, .tps, .trp, .ts, .tts, .uvu, .vob, .webm, .wm, .wmv, .wmx, .WTV, .wvx
• Images
  • .arw, .avcs, .bmp, .cr2, .crw, .dds, .dib, .dng, .emf, .erf, .gif, .heic, .heics, .heif, .heifs, .ico, .jfif, .jpe, .jpeg, .jpg, .jxr, .kdc, .mdi, .mrw, .nef, .nrw, .orf, .pano, .pef, .png, .psd, .raf, .raw, .rle, .rw2, .rwl, .sr2, .srw, .svg, .tif, .tiff, .wdp, .wmf, .xbm
• Archives
  • .001, .7z, .arc, .arj, .B64, .BHX, .bz, .bz2, .cab, .gz, .hqx, .img, .iso, .kgb, .lha, .lz, .lzh, .LZS, .MIM, .MIME, .r00, .r01, .r02, .r03, .r04, .r05, .r06, .r07, .r08, .r09, .r10, .r11, .r12, .r13, .r14, .r15, .r16, .r17, .r18, .r19, .r20, .r21, .r22, .r23, .r24, .r25, .r26, .r27, .r28, .r29, .rar, .rev, .tar, .taz, .tbz, .tbz2, .tgz, .tlz, .txz, .TZ, .uu, .uue, .VHD, .VMDK, .wjf, .wmz, .wsz, .wzcloud, .wzconfig, .wzmul, .wzsul, .wztheme, .XX, .xxe, .xz, .YFS, .z, .z00, .z01, .zip, .zipx, .zoo
• Certificates
  • .cat, .cer, .crl, .crt, .der, .p10, .p12, .p7b, .p7c, .p7m, .p7r, .p7s, .pem, .pfx, .pko, .spc, .sst, .stl
• Remote Desktop settings
  • .rdp, .rdg
• Remote assistance
  • .msrcincident
• Contact & calendar files
  • .contact, .ics, .vcf
• Executable
  • .application, .com, .cpl, .exe, .ocx, .pif, .scr, .wcx, , wfx, wlx, wdx
• Executable requiring extra effort to load
  • .386, .dll, .drv, .local, .manifest, .rll, .sys, .vbx, .vxd (legacy)
• Microsoft Installer
  • .inf, .msi, .msp, .msu
• Batch files
  • .bat, .cmd
• MSHTA
  • .hta
• Java Script
  • .js, .jse
• Visual Basic Script
  • .vbe, .vbs
• Windows Script File
  • .wsf, .wsh
• Old moniker to a Windows Script Component
  • .sct, .wsc
• Registry file
  • .reg
• Windows Explorer Command
  • .scf
• Shortcuts
  • .lnk
• Internet Shortcut
  • .url
• Web Point And Print File
  • .webpnp
• Gadget files (legacy, Vista and Win7 only)
  • .gadget
• Shell Scrap (legacy, XP-only)
  • .shs
• Help files
  • .chm, .hlp, .hxa, .hxc, .hxd, .hxe, .hxf, .hxh, .hxi, .hxk, .hxq, .hxr, .hxs, .hxt, .hxv, .hxw
• Other known malicious
  • .iqy, .settingcontent-ms
• Various of interest
  • .group, .odc, .rqy, .vsto, .mht, .mhtml, .website, .WMD, .xbap
• Various -ms files
  • .accountpicture-ms, .appcontent-ms, .appref-ms, .devicemanifest-ms, .devicemetadata-ms, .dvr-ms, .library-ms, .mfcribbon-ms, .search-ms, .searchConnector-ms, .slupkg-ms, .xrm-ms
• Java
  • .jar, .class, .java, .war
• Perl
  • .pl
• Python
  • .py, .pyc, .pyd, .pyw, .pyz
• Ruby
  • .rb

There is also a funny file extension called .rat with a MIME name application/rat-file 🙂