What is the TLS file format?
A .tls file is a logon-screen theme package created by TuneUp Styler, a module bundled with TuneUp Utilities from TuneUp Software. The file packages everything needed to replace the standard Windows welcome screen - typically one or more background images alongside positioning metadata that instructs TuneUp Styler how to apply the theme.
The format targets Windows XP, Vista, and 7, operating systems where the logon-screen UI could be replaced through software hooks. The .tls container is a proprietary binary package with no published magic signature; it is recognised only by TuneUp Styler itself. Some files have an archive-like internal structure and can be partially inspected with 7-Zip, though the internal layout is not officially documented.
TuneUp Software was acquired by AVG in 2011, and the product line eventually became AVG PC TuneUp (now under Avast/Gen Digital). Classic TuneUp Styler logon-screen customisation is no longer possible on modern Windows because Windows 8 and later removed the replaceable logon-screen UI entirely, making .tls files effectively obsolete.
Other TuneUp Styler theme formats include .TVS (visual styles), .TDL (desktop-look packages), and .TSA (TuneUp Styler archives). Note that .tls is also used by Sony / MAGIX Sound Forge for an unrelated audio time-locator sidecar file - if your file originates from an audio project rather than a TuneUp Utilities installation, it belongs to that separate format. The Windows .THEME format handles broader desktop appearance settings by contrast.
Security & safety
RISK: MEDIUMA TuneUp .tls logon theme modifies Windows system UI, so historically applying one required system-level changes - only apply themes from sources you trust, and avoid them entirely on modern Windows where the mechanism is unsupported and could destabilise the logon screen. The classic TuneUp suite is discontinued, so don't download it from third-party 'free TuneUp' mirrors, which frequently bundle adware/PUPs. If your .tls is actually a harmless Sound Forge markers file, it carries no such risk. Scan any file from an untrusted source.
Format details
in a nutshell- Sony / MAGIX Sound Forge time-locator (markers) file - Sound Forge audio editor saves a list of time markers/locators as .tls alongside an audio file.
- Generic tool/settings file - A few utilities use .tls for their own list/settings data; identify by the creating program.
Programs that open TLS files
Windows3 apps
TuneUp Utilities (TuneUp Styler) - legacy
Paid On an old install, open TuneUp Styler and import/apply the .tls logon screen. The classic suite is discontinued; this only works on legacy versions/older Windows.
Sony / MAGIX Sound Forge (if it's an audio .tls)
Paid If the .tls is a Sound Forge time-locator file, open the matching audio in Sound Forge and load its markers.
7-Zip (to inspect contents)
Open-source Try opening the .tls as an archive to see if it's a package you can extract images from; helps identify an unknown .tls. Technical details
deep spec| Format type | Proprietary binary logon-screen theme package |
| Developer | TuneUp Software (acquired by AVG in 2011, later Avast/Gen Digital) |
| Target operating systems | Windows XP, Windows Vista, Windows 7 |
| Byte order | Little-endian (Windows binary) |
| Container contents | Bundled logon-screen background images plus Styler metadata for placement and installation |
| Bundled image color depth | Typically 24-bit or 32-bit, depending on the packaged bitmaps or PNGs |
| Typical file size | A few KB to several MB, depending on bundled graphic assets |
| Applied via | TuneUp Styler module inside TuneUp Utilities - applied as a theme, not opened as a document |
| Archive compatibility | Internal structure is archive-like; contents can often be inspected with 7-Zip |
| MIME type | application/octet-stream |
| Magic bytes | No published file signature; identified by application association only |
| Extension conflict | The `.tls` extension is also used by Sony/MAGIX Sound Forge for audio time-locator (marker) sidecar files - an entirely separate format |
| Obsolete on | Windows 8 and later (Microsoft removed the replaceable logon-screen UI) |
| Related theme formats | Part of TuneUp Styler's theme ecosystem alongside `.tvs` (visual styles), `.tdl` (desktop look), and `.tsa` (Styler archives) |
| Released | TuneUp Utilities Styler era (mid-2000s) |
| Latest version | Legacy - TuneUp Utilities was rebranded AVG PC TuneUp and the classic suite is discontinued |
TLS conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about TLS files.
