Windows Program Manager group file (.grp)
.grp file signature | application/octet-stream
Windows Program Manager group files are a legacy Microsoft format used by Windows 3.x to store program groups and their associated shortcut definitions. They were used by Program Manager to organize applications, documents, and system tools into grouped launchable entries. The format is obsolete and generally safe to open, though files from untrusted sources should still be handled cautiously because they may reference legacy executables or paths.
Magic Bytes
Offset 0
50 4D 43 43
Sources: Wikipedia, Gary Kessler
Extension
.grp
MIME Type
application/octet-stream
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .grp files in Python
def is_grp(file_path: str) -> bool:
"""Check if file is a valid GRP by magic bytes."""
signature = bytes([0x50, 0x4D, 0x43, 0x43])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .grp files in Node.js
function isGRP(buffer: Buffer): boolean {
const signature = Buffer.from([0x50, 0x4D, 0x43, 0x43]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .grp files in Go
func IsGRP(data []byte) bool {
signature := []byte{0x50, 0x4D, 0x43, 0x43}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/grp
curl https://filesignature.org/api/v1/grp
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .grp file?
A .grp file is a Windows Program Manager group file file. Windows Program Manager group files are a legacy Microsoft format used by Windows 3.x to store program groups and their associated shortcut definitions. They were used by Program Manager to organize applications, documents, and system tools into grouped launchable entries. The format is obsolete and generally safe to open, though files from untrusted sources should still be handled cautiously because they may reference legacy executables or paths.
What are the magic bytes for .grp files?
The magic bytes for Windows Program Manager group file files are 50 4D 43 43 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .grp file?
To validate a .grp file, read the first bytes of the file and compare them against the known magic bytes (50 4D 43 43) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .grp files?
There is no officially registered MIME type for .grp files. Systems typically use application/octet-stream as a generic fallback when handling this format.
Is it safe to open .grp files?
Windows Program Manager group file (.grp) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.