What is the FRX file format?
.frx is a developer file format. .frx files store binary data and resources used for creating forms in Visual Basic. They travel paired with a same-named .frm form file: the .frm holds the form's text layout, while the .frx holds binary data that cannot be expressed as plain text - embedded icons, bitmaps, and large string properties referenced by byte offset from the .frm.
.frx files only store additional resources needed by the given form. .frx files are automatically generated by the development environment even if they remain empty. You never create or open an .frx directly - the VB IDE manages it automatically, and losing it while its .frm still holds offset references will corrupt the form.
Visual Basic is a high-level programming language developed by Microsoft. Visual Basic was designed as an application-creation language and tool. The language is based on BASIC. Although Visual Basic was a popular tool, most developers avoid it if possible. Visual Basic is the subject of many jokes and anecdotes, some of which touch upon the topic of empty .frx files.
The .frx format was introduced in Visual Basic 4.0 and became standard in VB5 and VB6 (1997-1998). It was superseded by .resx XML resource files when VB.NET launched in 2002. Note: Visual FoxPro uses the same .frx extension for report files, which are DBF-style tables with an entirely different structure.
Security & safety
RISK: LOWAn .frx is passive binary data with no scripting, so the file itself is low risk. The real caution is with the VB6 project it belongs to: legacy VB6 source from untrusted sources can contain code that does anything once compiled and run. Treat the project, not the .frx, as the thing to vet. There is no need to download dubious 'FRX viewer' utilities - they don't meaningfully view this format.
Format details
in a nutshell- Visual FoxPro Report File - A report layout for FoxPro/Visual FoxPro stored as a DBF-format table (paired .frt memo); the original db_name referred to this type.
- Adobe FrameMaker MIF Reference (.frx) - Occasionally seen as a FrameMaker-related reference file; rare and unrelated to VB.
Programs that open FRX files
Windows3 apps
Visual Basic 6.0 (IDE)
Paid Open the project's .vbp (not the .frx directly); VB6 loads the .frm and reads the paired .frx automatically.
Visual Studio (with VB6 migration tools)
Freemium Use a VB6 upgrade/migration add-in to import the legacy project; Visual Studio converts forms and their .frx resources.
Resource viewer (e.g. Resource Hacker) - extraction only
Free Not a proper opener, but can sometimes carve out embedded icons/bitmaps from an .frx blob. Technical details
deep spec| Format type | Binary companion/resource file for a Visual Basic form - not a standalone document |
| Encoding | Binary (opaque byte stream); no plain-text representation |
| Byte order | Little-endian |
| File signature | No fixed magic bytes - identified only by sharing its base name with a paired `.frm`; the IDE maps form to resource by filename, not by signature |
| Paired file requirement | Must accompany a same-named `.frm` in the same project directory; removing or desyncing the `.frx` corrupts the form and prevents it from loading |
| Content types stored | Embedded icons (`.ico`), bitmaps (`.bmp`), and large binary string properties from form controls that cannot be stored as text in the `.frm` |
| Referencing mechanism | Binary property values are addressed by byte offset; those offsets are stored inline in the paired `.frm` text file |
| Internal version field | Absent - tied implicitly to the VB version that saved the project (VB4, VB5, or VB6); no independent version marker inside the file |
| Checksum / integrity | No built-in checksum; data integrity depends entirely on the byte offsets in the `.frm` remaining in sync with the `.frx` content |
| Typical file size | 0 bytes (when empty) to several MB, depending on the number and size of embedded images and icons |
| Associated OS | Windows only |
| IDE integration | Created and maintained exclusively by the Visual Basic IDE; never manually authored or edited by the developer |
| MIME type | `application/octet-stream` |
| Superseded by | `.resx` XML resource file in VB.NET / Visual Studio .NET (2002 onward) |
| Extension namespace collision | Visual FoxPro also uses `.frx` for report files - a DBF-style table beginning with bytes `0x30`-`0x32`, entirely unrelated in structure to the VB6 format |
| Released | Visual Basic 4.0 era (1995); standard in Visual Basic 5.0/6.0 (1997-1998) |
| Latest version | Visual Basic 6.0 (1998); unchanged since - VB6 mainstream support ended March 2008 |
FRX conversions
Community Q&A
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