What is the RMSKIN file format?
A .rmskin file is the official self-installing package format used by Rainmeter, the Windows desktop customization application. The file bundles one or more skins together with optional resources - fonts, plugins (32-bit and 64-bit .dll files), and saved Layouts - into a single distributable archive that the Rainmeter Skin Installer handles automatically on double-click.
Structurally, a .rmskin package is a 7-Zip archive compressed with LZMA, with a small custom footer appended at the very end of the file. The footer contains the literal ASCII marker RMSKIN, the byte size of the embedded archive, and a flags field that controls install behavior. Because the body is a standard .7z archive, tools like 7-Zip can open a .rmskin to inspect or extract its contents, though the proper installation path is through Rainmeter's bundled Skin Installer.
Inside the archive, a mandatory RMSKIN.ini manifest declares metadata and controls what gets installed:
Name,Author, andVersionfields identify the packageMinimumRainmeterandMinimumWindowsenforce compatibility requirementsLoadType/Loaddetermines which skin or layout is activated after installation
Skins are stored under a Skins/ directory; shared resources go into @Vault/; plugins land in Plugins/32bit/ and Plugins/64bit/ subdirectories. The format is Windows-only, mirroring Rainmeter's own Windows exclusivity.
Security & safety
RISK: MEDIUMMost .rmskin packages are harmless .ini configs and images, but two real cautions exist: (1) skins can bundle Rainmeter PLUGINS (DLLs) that run as native code when the skin loads, so a malicious package could ship a harmful plugin - install skins only from reputable authors/communities; (2) the Skin Installer confirmation dialog lists exactly which skins and plugins will be added - read it before clicking Install. To be safe, open the .rmskin in 7-Zip first and check for unexpected .dll files. Only run skins from trusted sources.
Format details
in a nutshellPrograms that open RMSKIN files
Windows2 apps
Rainmeter
Open-source Install Rainmeter, then double-click the .rmskin - the bundled Skin Installer opens, review the contents and click Install. 
7-Zip
Open-source Right-click > 7-Zip > Open archive to inspect/extract contents WITHOUT installing (it's a 7z archive). For viewing, not for using the skin. Technical details
deep spec| Container format | 7-Zip (LZMA) archive body with a custom Rainmeter installer footer appended at the end of the file |
| Magic bytes | 7-Zip signature 37 7A BC AF 27 1C at byte offset 0; ASCII string RMSKIN embedded in the trailing footer at the tail |
| Compression algorithm | LZMA (Lempel-Ziv-Markov chain algorithm), the same engine used by standard .7z archives |
| Install manifest | RMSKIN.ini at the archive root; declares Name, Author, Version, MinimumRainmeter, MinimumWindows, LoadType, and Load |
| Footer fields | Archive byte-size for size validation, installer behavior flags, and the ASCII marker RMSKIN |
| Integrity check | Footer stores the archive byte-size for validation only; no cryptographic hash or digital signature is applied |
| Plugin packaging | 32-bit and 64-bit .dll plugin files placed in Plugins/32bit/ and Plugins/64bit/ subdirectories inside the archive |
| Font bundling | Custom fonts stored in the Fonts/ directory; copied to Rainmeter's own font store during installation |
| Archive directory layout | Skins/, @Vault/ (shared resources), Layouts/, Plugins/, and Fonts/ at the archive root |
| Activation control | LoadType and Load keys in RMSKIN.ini specify which skin or layout Rainmeter activates immediately after installation completes |
| Version gating | MinimumRainmeter and MinimumWindows fields in RMSKIN.ini block installation on incompatible Rainmeter or Windows versions |
| Byte order | Little-endian, consistent with the 7-Zip format and Windows platform conventions |
| MIME type | application/octet-stream (no dedicated registered MIME type exists for the .rmskin format) |
| Platform compatibility | Windows only; Rainmeter has no Linux or macOS port, so .rmskin packages are exclusively a Windows format |
| Released | Around 2011 (Rainmeter 2.x introduced the .rmskin installer format) |
| Latest version | Rainmeter skin installer footer format used by Rainmeter 4.x (current) |
| Specification | docs.rainmeter.net |
RMSKIN conversions
Community Q&A
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