SumatraPDF Settings Not Saving: How to Fix It

When SumatraPDF settings are not saving, the symptom is usually straightforward: you change an option, theme, shortcut, tab preference, zoom mode, or view default, but the old behavior returns after you restart the application. The most common causes are an unwritable settings file, confusion between installed and portable copies, an improper shutdown, a syntax error in advanced settings, or another Windows tool restoring or deleting the file. Some apparent settings problems are actually file-association, document-format, rendering, or printing issues. The steps below help you identify the correct category before making broad changes.

1. Confirm the Symptom With One Simple Test

Begin with a controlled test instead of changing several options at once. This establishes whether SumatraPDF cannot save any preferences or whether one particular behavior is controlled elsewhere.

1. Open the copy of SumatraPDF you normally use.
2. Change one obvious, reversible preference, such as a display or interface option.
3. Close every SumatraPDF window normally.
4. Wait a few seconds, then reopen SumatraPDF from the same shortcut or executable.
5. Check whether the test preference remains changed.

If the preference survives the restart, general settings persistence is working. Stop treating the issue as a damaged settings file and investigate the specific option, document, shortcut, association, or external component involved.

If the preference resets, continue with the settings-file checks below. Avoid changing more options until you identify the cause, because multiple simultaneous changes make it harder to verify a fix.

1.1 Confirm That SumatraPDF Exits Cleanly

Some application state is written or finalized during a normal exit. Closing Windows abruptly, ending SumatraPDF through Task Manager, terminating a remote session, or shutting down immediately after making a change can prevent that process from completing.

Make one test change, close all SumatraPDF windows using the normal close command, and verify in Task Manager that no SumatraPDF process remains. Reopen it only after the process has ended. Success means the setting remains selected after a second normal restart.

If this works, no reset or reinstall is necessary. The problem was the exit sequence, so stop changing settings and use a normal application close after future preference changes.

1.2 Make Sure You Reopen the Same Copy

Windows users sometimes have both an installed copy and a portable copy of SumatraPDF. A pinned taskbar icon may start one copy, while double-clicking a PDF may start another. Each copy can read a different settings file, making preferences appear to disappear.

Open SumatraPDF using the shortcut that shows the problem, then identify its executable location through Task Manager or the shortcut properties. Repeat this check when opening a document by double-clicking it. If the paths differ, update the shortcut or file association so every launch method uses the intended executable.

2. Check the Setting, Command, Association, or Format Directly

Not every behavior that looks like a forgotten preference is stored as a normal global setting. SumatraPDF may remember document-specific state, Windows may choose another application, a command-line option may override a preference, or the source format may require different handling.

2.1 Separate Global Preferences From Document State

Test the behavior with one simple local PDF stored in a normal user folder. Then test a second document. If the setting works for one file but not another, general persistence is probably functioning.

Document-specific factors can include page dimensions, embedded layout information, remembered reading position, unusual metadata, or the way a particular format is rendered. A fixed-layout PDF does not behave exactly like a reflowable eBook, comic archive, CHM file, DjVu document, XPS file, or image collection.

Success means the same global preference survives a restart and behaves consistently on ordinary test files. Once that happens, stop resetting SumatraPDF and focus on the affected document or format.

2.2 Inspect the Shortcut for Command-Line Overrides

A desktop shortcut, script, launcher, or file manager can start SumatraPDF with command-line arguments. Those arguments may create behavior that differs from what the graphical preferences suggest.

Right-click the shortcut, open its properties, and inspect the Target field. The executable path may be followed by arguments. For testing, launch the executable directly without custom arguments. Do not remove organizational or accessibility options permanently until you understand why they were added.

If direct launching preserves and applies the preference, the settings file is probably healthy. Correct the shortcut or external launcher rather than deleting saved preferences.

2.3 Verify Windows File Associations

If SumatraPDF looks correct when opened directly but behaves differently after you double-click a document, Windows may be opening another PDF reader or another SumatraPDF installation.

Use Windows Settings to check the default application for the affected extension, such as PDF, EPUB, MOBI, CBZ, CBR, CHM, DjVu, or XPS. You can also right-click a test document, choose Open with, and select the intended SumatraPDF executable.

Success means double-clicking the file opens the same executable you tested directly. If that resolves the problem, do not edit the settings file.

3. Check Windows and External Factors When Relevant

Windows permissions and third-party utilities can interfere with genuine settings persistence. Other factors, including format support, rendering tools, printer drivers, or document restrictions, matter only when the symptom is limited to opening, displaying, or printing particular files.

3.1 Check Installed Versus Portable Mode

A standard installed copy normally keeps its user settings under the current Windows account's local application data directory:

%LOCALAPPDATA%\SumatraPDF\SumatraPDF-settings.txt

You can paste %LOCALAPPDATA%\SumatraPDF into File Explorer's address bar. A portable copy generally keeps SumatraPDF-settings.txt beside the portable executable. This requires the executable's folder to be writable.

Portable copies often fail to save preferences when run from read-only media, a protected program directory, a ZIP archive, a network location with restricted access, or a folder controlled by another account. Move the complete portable application to a normal writable folder owned by your user account, such as a dedicated folder inside Documents, and test again.

Success means the settings file's modified time changes after you make a preference change and close SumatraPDF normally.

3.2 Test Write Permissions Without Weakening Security

Locate the applicable settings folder and check whether your account can create and delete a harmless temporary text file there. If it cannot, SumatraPDF may also be unable to update its settings.

Do not solve this by granting broad permissions to protected Windows folders or by running the reader as administrator every day. Instead, use the installed version with its normal AppData location, or place the portable version in a folder your account owns.

Also inspect the properties of SumatraPDF-settings.txt. If the file is marked read-only, clear that attribute only if you know it was not deliberately enforced by an administrator. On managed computers, ask the administrator before changing policies or permissions.

3.3 Check Cloud Sync, Backup, and Cleanup Utilities

Cloud synchronization, profile restoration, security software, and cleanup utilities can replace or remove configuration files. This is especially relevant when preferences survive one restart but disappear after signing in, rebooting Windows, running a cleaner, or switching computers.

• Check whether the portable folder is inside OneDrive, Dropbox, or another synchronized location.
• Review cleanup rules that target AppData, application histories, or text configuration files.
• Look for conflict copies or restored versions of the settings file.
• Temporarily pause the relevant utility for one controlled test, if permitted.

Success means the file remains present with the expected modified time after the triggering event. Add a narrow exclusion for the settings file or move the portable copy to a nonsynchronized local folder. Do not disable security protection broadly.

3.4 Distinguish Persistence From Rendering or Printing Problems

If preferences save correctly but one document will not open, render, or print, resetting preferences may not help. Test another known-good local file of the same format and a basic PDF.

Older PostScript-related workflows may depend on Ghostscript or another external conversion tool. Media-rich or unusual content may depend on Windows components, codecs, or format support. Printing behavior can be influenced by the selected printer, its driver, the print queue, and printer-specific settings.

Update or reinstall an external component only when the failure is tied to that component. If a basic PDF opens and prints normally while one source file does not, investigate the file, format, or printer path. Respect document permissions and access controls rather than attempting to bypass them.

4. Inspect or Reset SumatraPDF-settings.txt Safely

The SumatraPDF-settings.txt file is central to persistent preferences. Inspecting it can confirm whether SumatraPDF is writing changes, but editing it carelessly can introduce syntax errors. Always preserve a working copy first.

4.1 Back Up the File Before Editing

1. Close every SumatraPDF window.
2. Confirm that the process has ended in Task Manager.
3. Open the installed or portable settings folder.
4. Copy SumatraPDF-settings.txt to a safe location.
5. Give the backup a clear name, such as SumatraPDF-settings-backup.txt.

Do not edit the file while SumatraPDF is running. The application may overwrite your manual changes when it exits, or your editor may conflict with an update being written by the program.

4.2 Look for Advanced-Settings Syntax Mistakes

Manual changes to advanced settings must preserve the file's expected structure. Missing braces, altered setting names, misplaced values, duplicated blocks, or unsupported text can cause an entry to be ignored or prevent part of the configuration from being interpreted as expected.

If the problem began immediately after manual editing, restore your backup and test again. Alternatively, compare only the edited lines with the applicable official documentation or a newly generated settings file. Avoid copying large configuration blocks from old forum posts because available options can change over time.

Success means SumatraPDF starts normally, the selected preference works, and the file remains valid after a normal close and reopen. Once confirmed, stop editing.

4.3 Rename the Settings File for a Reversible Reset

If the file appears corrupted or you cannot identify the bad entry, use a reversible reset:

1. Close SumatraPDF completely.
2. Back up the existing settings file.
3. Rename it to SumatraPDF-settings.old.txt.
4. Start SumatraPDF and allow it to create fresh settings.
5. Change one test preference, close normally, and reopen.

Renaming is safer than immediate deletion because it preserves shortcuts and preferences that you may want to recover. Do not copy the entire old file over the new one, because that may restore the original problem. Reapply only necessary options in small groups, testing after each group.

If a fresh file also fails to retain one simple setting, the likely cause is the folder, permissions, launch path, shutdown process, or an external utility rather than the contents of the old file.

5. Run a Clean Temporary Test Before Reinstalling

A clean test separates SumatraPDF itself from the existing configuration without permanently removing anything. This is more informative than reinstalling immediately, because reinstalling may leave the same user settings in AppData.

1. Back up and rename the current settings file.
2. If appropriate, use an official clean portable copy in a new local writable folder.
3. Launch it directly rather than through an old shortcut.
4. Open a basic local PDF that is known to work.
5. Change one obvious preference.
6. Close the application normally and confirm the process ends.
7. Reopen the same executable and check the preference.

If the clean copy saves the setting, the original installation path, shortcut, settings file, or external launch method is responsible. Compare those elements one at a time.

If the clean portable copy cannot save settings in a writable local folder, check security software, managed-device policies, profile problems, and cleanup tools. Reinstall only after those checks. Download installers or portable packages from the official SumatraPDF site rather than an unofficial software mirror.

Success looks like the test preference surviving two normal restarts of the same executable. At that point, stop making changes and restore only the preferences you actually need.

6. Quick Fix Checklist

• Change one simple preference and close every SumatraPDF window normally.
• Confirm that Task Manager shows no remaining SumatraPDF process.
• Verify that shortcuts and file associations open the same executable.
• For an installed copy, inspect %LOCALAPPDATA%\SumatraPDF.
• For a portable copy, inspect the folder containing the executable.
• Confirm that your account can write to the applicable folder.
• Check whether the settings file's modified time changes after exit.
• Back up the settings file before making manual edits.
• Undo syntax changes that preceded the problem.
• Rename the settings file to perform a reversible reset.
• Test outside cloud-synchronized or automatically cleaned folders.
• Use a clean local test before reinstalling.
• Treat format, rendering, and printing failures separately when settings otherwise persist.

7. Frequently Asked Questions

7.1 Where Is SumatraPDF-settings.txt Located?

For a normally installed copy, look in %LOCALAPPDATA%\SumatraPDF\SumatraPDF-settings.txt. Paste %LOCALAPPDATA%\SumatraPDF into File Explorer to reach the folder for the current Windows account. A portable copy generally stores the file alongside its executable.

7.2 Can I Delete SumatraPDF-settings.txt?

Yes, SumatraPDF can create fresh settings, but renaming the file is safer than deleting it. Close SumatraPDF, back up the file, and rename it. This gives you a reversible reset and preserves any custom shortcuts or preferences you may later want to recover.

7.3 Why Do Settings Save When Opening SumatraPDF Directly but Not From a PDF?

The PDF file association may point to another SumatraPDF executable or a different reader. Compare the executable launched from your normal shortcut with the one launched by double-clicking a PDF. Update the Windows default application if they differ.

7.4 Why Do My Settings Disappear After a Reboot?

A cleanup utility, profile-restoration system, cloud synchronization conflict, or managed-device policy may be replacing the settings file. Check its modified time before and after rebooting, then review the tools or policies that operate during sign-in and shutdown.

7.5 Does Reinstalling SumatraPDF Reset Its Settings?

Not necessarily. User configuration stored in AppData may remain after an application reinstall. A backed-up, renamed settings file or a clean portable test is usually a better diagnostic step because it directly tests whether the existing configuration is involved.

7.6 When Should I Stop Troubleshooting Settings?

Stop once one simple preference survives two normal restarts of the same executable. If only one file, format, printer, or launch method still fails, settings persistence is working. Continue with the document, association, rendering component, printer driver, or external tool related to that narrower symptom.