How we store settings

Where we store settings #

Persisted data is stored in the SumatraPDF-settings.txt file.

In the portable version, the file is stored in the same directory as the SumatraPDF executable. In the installed version, it’s in the %LOCALAPPDATA%\SumatraPDF directory.

Starting with version 1.6, we also persist thumbnails for the “Frequently read” list. They are stored as .png files in the sumatrapdfcache subdirectory.

Override the directory with -appdata <path> on the command line. See Installation.

See https://www.sumatrapdfreader.org/settings/settings for information about all the settings.

How settings apply #

Not every setting works the same way. Settings apply in three layers, and knowing them explains why a changed setting sometimes seems to have no effect.

1. Global defaults (first open) #

Settings like DefaultDisplayMode and DefaultZoom in advanced settings apply when you open a document for the first time, when there is no saved state for that file yet.

The Settings → Options dialog (“remember these settings for each document”) writes global defaults into the same settings file. The defaults do not retroactively change files you have already opened.

2. Per-document state (reopen) #

When RememberStatePerDocument = true (default), SumatraPDF saves display settings per file in the FileStates section: zoom, scroll position, view mode, sidebar width, tab color, etc.

The next time you open that file, the saved state is used instead of the global defaults, which is why changing “default two-page view” does not affect a PDF you have opened before. See FAQ.

To reset one file: delete its [[FileStates]] block from the settings file, or delete the entire settings file to reset everything.

3. Restart-required settings #

Some settings apply only after restarting SumatraPDF:

UseTabs: tabbed or separate windows, for new windows only
Others noted in advanced settings (e.g. some UI layout options)

ReuseInstance and most color/theme changes take effect immediately or on the next file open.

Session restore #

Setting	Effect
`RestoreSession = true`	On startup, reopen the tabs and windows still open at last close (`SessionData`)
`RememberOpenedFiles = true`	Keep a history of opened files (`FileStates`) for Home and the `#` command palette. Also required for saving `SessionData`
`LazyLoading = true`	When restoring session, load tab content only when the tab is selected

FileStates and SessionData hold different things. FileStates is the history, so a file stays there after you close it, until it drops off the list or you clear the history (File > Clear History). SessionData only lists what was still open when the last window closed. If you close a tab before closing the window, it is gone from SessionData but remains in FileStates.

-for-testing skips restore and does not save settings.

What is not in the settings file #

Unsaved annotations: kept in memory until you save or discard. See Editing annotations
Installer / restrict policy: sumatrapdfrestrict.ini beside the executable. See Configure for restricted use

Reset to defaults #

Delete SumatraPDF-settings.txt. SumatraPDF recreates it on next launch with factory defaults.