AUP3-SHM File

What are AUP3-SHM files and how to open them

Are you having problems opening an AUP3-SHM file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AUP3-SHM files.

What is an AUP3-SHM file?

An .AUP3-SHM file is an Audacity 3 Temporary Data file.

Audacity 3 Temporary Data files hold short-term database information used by Audacity during an open session. They are part of how Audacity manages projects in its newer "unitary" project format, which stores all tracks, metadata, settings and clip edits in a single SQLite database. These temporary files support ongoing edits and recording until the project is closed.

Written automatically by Audacity on Windows and Linux when a project in the newer format is opened or modified, these files work alongside its main .aup3 database file. One such file tracks changes not yet committed to the main database (the WAL file), while this one acts as a shared-memory index that aids those operations. Audacity deletes both when the project is closed, so they are not intended for long-term storage or external opening.

The format is internally recognized by specific byte patterns: it begins with the signature 0x18E22D0000000000 at offset 0, followed by 0x0000000100010002000000 at offset 9, and another marker 0x000000 at offset 21.

How to open AUP3-SHM files

Important: Different programs may use files with the AUP3-SHM file extension for different purposes, so unless you are sure which format your AUP3-SHM file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 22, 2026

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