What is the CRD file format?
.crd files store contact and reference data created by CARDFILE.EXE, the index-card accessory that Microsoft bundled with Windows from version 1.0 (1985) through Windows 95. Each file begins with the magic bytes MGC (or RRG for the double-byte character set variant) at offset 0, identifying it as a genuine Cardfile database.
What kind of data do .crd files contain?
.crd files store such information as:
- names,
- addresses,
- phone numbers,
- email addresses,
- free-text notes and embedded images.
.crd files are in a way similar to physical index cards or a rolodex, with added convenience supplied by Windows Cardfile - cards are alphabetically sorted and searchable by keyword.
What are .crd files used for?
Personal contact information stored in .crd files can be retrieved quickly by name look-up. Because Cardfile was a built-in Windows accessory, .crd databases were widely used in homes and small offices during the late 1980s and early 1990s as a lightweight contact manager.
How can .crd files be used today?
Although CARDFILE.EXE is no longer included with modern Windows, third-party tools such as AZZ Cardfile and CRD Reader can still open .crd files. Data can be migrated to modern formats such as vCard or a CSV file for use in current address-book software.
Security & safety
RISK: LOWA Cardfile .crd is passive data (text cards) and is safe to open; very old cards could embed an OLE object, but that's rare. The real risk is third-party "CRD viewer" download sites that bundle adware/PUPs - stick to the original applet, AZZ Cardfile's official site, or the open CRD Reader. Don't confuse this .crd with security tokens: CardSpace InfoCards are a different, dead technology.
Format details
in a nutshell- Guitar/Ukulele Chord Chart - Plain-text song sheet with chord names over lyrics, saved as .crd by some chord apps.
- OrCAD Capture Schematic Data - Schematic-related data file produced by Cadence OrCAD Capture EDA software.
Programs that open CRD files
Windows3 apps
AZZ Cardfile
Paid Maintained Cardfile-compatible PIM; File > Import opens classic .crd files and lets you save/export them.
CARDFILE.EXE (original applet)
Free Copy cardfile.exe from an old Windows (or an archive), run it, File > Open the .crd. The 32-bit build runs on Windows 10/11; the 16-bit one needs an emulator.
CRD Reader (eakondratiev)
Free Free console tool that reads a .crd and prints/exports the card text - no Cardfile needed. Technical details
deep spec| Magic bytes | `MGC` (3 bytes at offset 0) for the classic Windows 3.x format; `RRG` for the double-byte character set (DBCS) variant |
| File structure | Proprietary binary format; not XML or plain text |
| Card record layout | Each card contains a fixed-size header, an index line (card title, approximately 40 characters), and a variable-length content block |
| Embedded objects | Supports OLE 1.0 embedded objects and clipboard-pasted bitmaps within individual cards |
| Character encoding | Windows ANSI (system code page, typically Windows-1252); the `RRG` variant extends support to double-byte characters for CJK locales |
| Compression | None - data is stored uncompressed |
| Sort order | Cards are sorted and indexed alphabetically by the index line, enabling fast look-up |
| Platform origin | Windows 1.0 (1985) through Windows 95; `CARDFILE.EXE` was not included by default from Windows XP onwards |
| MIME type | `application/octet-stream` (no dedicated MIME type registered) |
| Developer | Microsoft (bundled Windows accessory `CARDFILE.EXE`) |
| Data types per card | Plain text notes, contact details, and optionally one embedded image or OLE 1.0 object |
| File size | Typically a few kilobytes to tens of kilobytes; grows linearly with card count and embedded objects |
| Third-party support | AZZ Cardfile and CRD Reader (eakondratiev) provide read/write access on current Windows versions |
| Related formats | Logically superseded by `.vcf` (vCard) for contact interchange; data can also be exported to `.csv` or `.txt` |
| Released | Cardfile shipped with Windows 1.0 (1985) through Windows 3.x; removed as a default app after Windows 95 |
CRD conversions
Community Q&A
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