Reserved file and URI scheme names
You can use URI associations to automatically launch your app when another app launches a specific URI scheme. But there are some URI associations that you can’t use because they are reserved. If your app registers for a reserved association, that registration will be ignored. This topic lists the reserved file and URI scheme names that are not available to your app.
Reserved file types
There are two types of reserved file types: file types reserved for built-in apps and file types reserved for the operating system. When a file type reserved for a built-in app is launched, only the built-in app will launch. Any attempt to register your app with that file type is ignored. Similarly, any attempt to register your app with a file type reserved for the operating system also will be ignored.
File types reserved for built-in apps
| .aac | .icon | .pem | .wdp |
| .aetx | .jpeg | .png | .wmv |
| .asf | .jxr | .pptm | .xap |
| .bmp | .m4a | .pptx | .xht |
| .cer | .m4r | .qcp | .xhtml |
| .dotm | .m4v | .rtf | .xltm |
| .dotx | .mov | .tif | .xltx |
| .gif | .mp3 | .tiff | .xml |
| .hdp | .mp4 | .txt | .xsl |
| .htm | .one | .url | .zip |
| .html | .onetoc2 | .vcf | |
| .ico | .p7b | .wav |
File types reserved for the operating system
The following file types are reserved for the operating system
| .accountpicture-ms | its | .ops | .url |
| .ade | .jar | .pcd | .vb |
| .adp | .js | .pif | .vbe |
| .app | .jse | .pl | .vbp |
| .appx | .ksh | .plg | .vbs |
| .application | .lnk | .plsc | .vhd |
| .appref-ms | .mad | .prf | .vhdx |
| .asp | .maf | .prg | .vsmacros |
| .bas | .mag | .printerexport | .vsw |
| .bat | .mam | .provxml | .webpnp |
| .cab | .maq | .ps1 | .ws |
| .chm | .mar | .ps1xml | .wsc |
| .cmd | .mas | .ps2 | .wsf |
| .cnt | .mat | .ps2xml | .wsh |
| .com | .mau | .psc1 | .xaml |
| .cpf | .mav | .psc2 | .xdp |
| .cpl | .maw | .psm1 | .xip |
| .crd | .mcf | .pst | .xnk |
| .crds | .mda | .pvw | |
| .crt | .mdb | .py | |
| .csh | .mde | .pyc | |
| .der | .mdt | .pyo | |
| .dll | .mdw | .rb | |
| .drv | .mdz | .rbw | |
| .exe | .msc | .rdp | |
| .fxp | .msh | .reg | |
| .fon | .msh1 | .rgu | |
| .gadget | .msh1xml | .scf | |
| .grp | .msh2 | .scr | |
| .hlp | .msh2xml | .shb | |
| .hme | .mshxml | .shs | |
| .hpj | .msi | .sys | |
| .hta | .msp | .theme | |
| .inf | .mst | .tmp | |
| .ins | .msu | .tsk | |
| .isp | .ocx | .ttf |
Reserved URI scheme names
| application.manifest | inffile | ms-settings:network-dialup | scrfile |
| application.reference | insfile | ms-settings:network-ethernet | scriptletfile |
| batfile | internetshortcut | ms-settings:network-mobilehotspot | shbfile |
| bing | javascript | ms-settings:network-proxy | shcmdfile |
| blob | jscript | ms-settings:network-wifi | shsfile |
| callto | jsefile | ms-settings:nfctransactions | smb |
| cerfile | ldap | ms-settings:notifications | stickynotes |
| chm.file | lnkfile | ms-settings:personalization | sysfile |
| cmdfile | mailto | ms-settings:privacy-calendar | tel |
| comfile | maps | ms-settings:privacy-contacts | telnet |
| cplfile | microsoft.powershellscript.1 | ms-settings:privacy-customdevices | tn3270 |
| dllfile | ms-accountpictureprovider | ms-settings:privacy-feedback | ttffile |
| drvfile | ms-appdata | ms-settings:privacy-location | unknown |
| dtmf | ms-appx | ms-settings:privacy-messaging | usertileprovider |
| exefile | ms-autoplay | ms-settings:privacy-microphone | vbefile |
| explorer.assocactionid.burnselection | ms-excel | ms-settings:privacy-speechtyping | vbscript |
| explorer.assocactionid.closesession | msi.package | ms-settings:privacy-webcam | vbsfile |
| explorer.assocactionid.erasedisc | msi.patch | ms-settings:proximity | wallet |
| explorer.assocactionid.zipselection | ms-powerpoint | ms-settings:regionlanguage | windows.gadget |
| explorer.assocprotocol.search-ms | ms-settings | ms-settings:screenrotation | windowsmediacenterapp |
| explorer.burnselection | ms-settings:batterysaver | ms-settings:speech | windowsmediacenterssl |
| explorer.burnselectionexplorer.closesession | ms-settings:batterysaver-settings | ms-settings:storagesense | windowsmediacenterweb |
| explorer.closesession | ms-settings:batterysaver-usagedetails | ms-settings:windowsupdate | wmp11.assocprotocol.mms |
| explorer.erasedisc | ms-settings:bluetooth | ms-settings:workplace | wsffile |
| explorer.zipselection | ms-settings:connecteddevices | ms-windows-store | wsfile |
| file | ms-settings:cortanasearch | ms-word | wshfile |
| fonfile | ms-settings:datasense | ocxfile | xbls |
| hlpfile | ms-settings:dateandtime | office | zune |
| htafile | ms-settings:display | onenote | |
| http | ms-settings:lockscreen | piffile | |
| https | ms-settings:maps | regfile | |
| iehistory | ms-settings:network-airplanemode | res | |
| ierss | ms-settings:network-cellular | rlogin |