| Extension | 描述 | 檔案格式 |
|---|
| c | C/C++ Source Code File | Developer Files |
| c00 | Corel Ventura Print File | Layout Files |
| c00 | Winace Split Archive File | 壓縮檔案 |
| cab | Windows Cabinet File | 壓縮檔案 |
| cache | Cache File | Misc Files |
| caj | China Academic Journals Fulltext Database File | 文字檔 |
| cam | Casio Image File | 圖檔 |
| camrec | Camtasia Studio Recorded File | 視頻檔案 |
| cap | Caption File | Desktop Publishing |
| cat | Advanced Disk Catalog File | 資料檔 |
| catalog | Catia Catalog File | 3D Files |
| cbf | Calender Builder File | Misc Files |
| cbr | Comic Book Archive File | 壓縮檔案 |
| cbz | Comic Book ZIP File | 壓縮檔案 |
| ccd | CloneCD Control File | 磁碟映像檔 |
| ccf | CryptLoad Download Link File | 網頁檔案 |
| cd | Philips/Optlmage Master Tool File | 磁碟映像檔 |
| cda | Compact Disc Audio File Shortcut | 聲音檔案 |
| cdb | Symbian OS Contacts Database File | 資料檔 |
| cdd | ConceptDraw Document File | 資料檔 |
| cdf | Component Definition File | Developer Files |
| cdg | Compact Disc Plus Graphics File | 圖檔 |
| cdi | DiscJuggler Image File | 磁碟映像檔 |
| cdm | Media Maker Disk Image File | 磁碟映像檔 |
| cdp | Visual Objects Developer File | Developer Files |
| cdr | CorelDRAW Image File | 圖檔 |
| cdt | CorelDraw Template File | 設定檔 |
| cdw | CadKey Organized Dialogue File | 資料檔 |
| cdx | CorelDraw Compressed Image File | 圖檔 |
| ceb | Apabi eBook File | Misc Files |
| cf | Sendmail Configuration File | 設定檔 |
| cfg | Configuration File | 設定檔 |
| cfm | Cold Fusion Template File | 網頁檔案 |
| cfp | Quicken Cash Flow Projection File | 資料檔 |
| cfr | Crossfire Replay file | 遊戲檔案 |
| cgd | Cricket Graph Data File | 資料檔 |
| cgi | Common Gateway Interface script | 執行檔 |
| chk | Recovered File Fragments | Misc Files |
| chm | Windows Help File | 文字檔 |
| chp | Corel Ventura Chapter File | 文字檔 |
| cht | Harvard Graphics Vector File | 圖檔 |
| chw | Compiled Help Index File | Misc Files |
| cl | i5 QCLSRS Source File | 文字檔 |
| cl | Articons Pro Cursor Library File | 圖檔 |
| class | Java Class File | Developer Files |
| clb | ICQ Contact List File | Misc Files |
| clg | Windows Catalog File | 系統檔案 |
| cli | Client Management System Customer File | 資料檔 |
| clm | COLIMO file | 3D Files |
| clpi | Blue-ray Disc Clip Information File | 視頻檔案 |
| cmap | Cmap Tools Concept Map File | Misc Files |
| cmd | Command Prompt File | 執行檔 |
| cmg | CMG File | 遊戲檔案 |
| cmp | Sharepoint Content Migration Package | 網頁檔案 |
| cmx | Corel Metafile Exchange File | 圖檔 |
| cnf | Configuration File | 設定檔 |
| cnt | Help Table Of Contents File | 系統檔案 |
| cod | Compiler Program Code | Developer Files |
| cof | COFFEE Script File | 3D Files |
| col | Autodesk Colour Palette File | 3D Files |
| com | DOS Command File | 系統檔案 |
| con | Concept Application Source File | 網頁檔案 |
| conf | Configuration File | 設定檔 |
| config | Configuration File | Developer Files |
| cont | Panasonic Camcorder File | 多媒體檔案 |
| cos | Creatures Source Code File | 遊戲檔案 |
| cpf | Clever Cache Profile File | Misc Files |
| cpi | AVCHD Clip Information | 視頻檔案 |
| cpp | C++ Language Source Code File | Developer Files |
| cpr | Cubase Project File | 聲音檔案 |
| cpt | Corel Photo-Paint Image File | 圖檔 |
| cr | Iris CT Bitmap Files | 圖檔 |
| cr2 | Canon Raw Image File | 圖檔 |
| crash | Mac OS X Crash Log File | 系統檔案 |
| crc | Total Commander CRC File | Misc Files |
| crdownload | Google Chrome Temporary File | Misc Files |
| crtx | Microsoft Chart Template File | 試算表檔案 |
| crw | Canon RAW Image File | 圖檔 |
| crx | Chrome Extension File | Plugin Files |
| cs | Visual C# Source File | Developer Files |
| csd | Compact Shared Document File | 文件檔案 |
| csf | Adobe Colour Settings File | 圖檔 |
| cso | Compressed ISO Image File | 磁碟映像檔 |
| css | Cascading Sheet Style File | Layout Files |
| csv | Comma Seperated Values | 資料檔 |
| ct | Continous Tone File | 圖檔 |
| ctg | Canon Catalog File | 聲音檔案 |
| ctl | Microsoft Visual Basic Control File | Developer Files |
| ctt | Messenger contacts file | 資料檔 |
| cue | Cue Sheet File | 磁碟映像檔 |
| cur | Windows Cursor File | 系統檔案 |
| cursorfx | CursorFX Graphic File | 圖檔 |
| curxptheme | CursorXP Theme File | 圖檔 |
| cva | ACD Canvas Sequence Set File | 圖檔 |
| cxf | Google Picasa Collage File | Misc Files |
| cxt | Protected Cast Member File | 文件檔案 |