SumatraPDF Annotations Missing After Reopen: How to Fix It

You add highlights, notes, or other marks to a PDF, close it, and later discover that the annotations have disappeared in SumatraPDF or are invisible in another viewer. This usually means one of four things happened: the changes were never saved, SumatraPDF reopened a different copy, Windows or a synchronization service replaced the edited file, or the annotations were saved in a form that another viewer does not display correctly. The steps below isolate those possibilities without requiring developer tools or risky changes.

1. Confirm the Symptom With One Simple Document Test

Before changing SumatraPDF settings or reinstalling anything, determine whether the problem affects one PDF, one storage location, or every document. A controlled test can separate an application problem from a file-specific problem in a few minutes.

1.1 Create a local writable test

1. Copy a non-sensitive PDF to a new folder under your Windows Documents folder.
2. Rename it to something unmistakable, such as annotation-persistence-test.pdf.
3. Open that exact file in SumatraPDF.
4. Add a small annotation using an annotation feature available in your installation.
5. Use the application's save command, commonly available through the File menu or a keyboard shortcut such as Ctrl+S.
6. Close the document completely, reopen it from the same folder, and check the annotation.

Do not rely only on closing the window. If the application asks whether to save changes, choose the save option and wait for it to finish. If no save command is available for the document, the format, file permissions, or current application capabilities may not permit annotation editing.

Success means the annotation remains after reopening the exact same file. If this test succeeds, stop changing global settings. SumatraPDF can persist annotations, and the original problem is more likely related to the source PDF, its location, or confusion between multiple copies.

1.2 Check whether the file was actually modified

Open File Explorer, right-click the test PDF, select Properties, and note its location, size, and modified time. After saving an annotation, refresh File Explorer and check the modified time again. A changed timestamp is useful evidence that a write occurred, although synchronization software can later replace the file or alter timestamps.

If the modified time does not change, confirm that you used a save command and that the file is writable. If the time changes but the annotation disappears after reopening, test the same PDF in another established PDF viewer. That reveals whether the annotation data is missing from the file or merely not being rendered.

2. Check the SumatraPDF Command, File Path, and Document Format

The phrase SumatraPDF annotations missing after reopen can describe several different failures. The most important distinction is whether the annotation was saved into the PDF at all.

2.1 Separate saved annotations from unsaved changes

An annotation visible during the current session is not proof that it has been written to disk. Treat annotations like edits in any other document application: use Save or Save As, respond carefully to close prompts, and verify the result by reopening the file.

If you close the document and explicitly discard changes, the annotations generally cannot be recovered from the unchanged PDF. Reinstalling SumatraPDF or resetting its settings does not reconstruct edits that were never saved. Recovery may be possible only if a cloud service, backup application, Windows File History configuration, or document-management system retained another version.

2.2 Make sure you reopened the same copy

Duplicate files are a common cause of apparently missing annotations. A PDF may exist in Downloads, Documents, an email attachment cache, a browser download folder, a cloud folder, and a temporary application folder at the same time.

While the annotated file is open, identify its full path through the document properties, title information, recent-files entry, or Save As dialog. Then use File Explorer to open that exact path. Compare the filename, folder, file size, and modified time rather than relying on the filename alone.

Also check the Windows file association. Double-clicking a PDF in File Explorer may open another viewer, even if you originally edited it in SumatraPDF. Conversely, a browser may display its downloaded or cached copy instead of the local file you edited. Right-click the known file, choose Open with, and select the viewer you intend to test.

Success means both SumatraPDF and the comparison viewer are opening the same physical file. Once the paths and timestamps match, stop modifying file associations unless double-clicking still launches the wrong application.

2.3 Confirm that the document is a PDF

SumatraPDF can read several formats, including eBooks, comics, CHM, DjVu, XPS, images, and PDFs. PDF annotations are stored according to the PDF format. An annotation-like action available for one format should not automatically be expected to persist as an embedded PDF annotation in another format.

Check the actual filename extension in File Explorer with file extensions visible. If the source is an image, XPS document, comic archive, DjVu file, or eBook, use features and workflows designed for that format. Converting or printing a document creates a different file and may remove searchable text, links, forms, layers, or editable annotations, so it should not be treated as an invisible save operation.

3. Check Windows, Cloud Storage, and PDF Restrictions

If local test annotations persist but annotations in the original document do not, focus on the original file and its storage location.

3.1 Remove read-only obstacles without weakening document restrictions

Right-click the PDF in File Explorer and select Properties. Check whether the Read-only attribute is selected. Also consider whether the file is on read-only media, in a protected network location, inside an archive, or in a folder where your Windows account lacks write access.

A PDF itself can also contain permissions that restrict changes, annotations, or printing. Respect those permissions. If editing is not authorized, request an editable copy or appropriate access from the document owner rather than attempting to remove protections.

If you are authorized to annotate but the current folder is not writable, use Save As to create a copy in your Documents folder. Add a test annotation to that copy, save it, and reopen it. Success means the problem was the original location or access policy, not a general SumatraPDF failure.

3.2 Test a local copy to avoid synchronization conflicts

OneDrive, SharePoint, Dropbox, network drives, email clients, and document-management tools can synchronize, replace, lock, or version files. A conflict may occur if the same PDF is open on multiple devices or if an older remote copy overwrites the locally edited file.

1. Close the PDF on other computers, phones, browser tabs, and viewer applications.
2. Copy the source PDF to a new local folder outside the synchronized location.
3. Add one annotation, save it, and confirm that the modified time changes.
4. Close SumatraPDF and reopen the local copy.
5. Open that same local copy in another PDF viewer.

If the local copy works, investigate the synchronization service's conflict files, version history, offline status, and upload completion. Return the tested file to shared storage only after confirming which copy is current. Avoid keeping two independently edited copies with the same filename.

3.3 Compare rendering in another PDF viewer

If SumatraPDF shows the saved annotation but another viewer does not, the annotation may be present while its visual appearance is handled differently. PDF viewers can differ in their support for annotation types, appearance data, layers, transparency, fonts, and interactive elements.

Test the exact same file in another reputable PDF viewer. Then interpret the result carefully:

• If no viewer shows the annotation, it was probably not saved into that copy.
• If SumatraPDF shows it but another viewer does not, investigate cross-viewer compatibility.
• If another viewer shows it but SumatraPDF does not, the file may contain an annotation or appearance that SumatraPDF is not rendering as expected.
• If each viewer shows different results, preserve the original and create small test copies before making further edits.

For a document that must be shared, verify the final file in the viewer used by its recipients. If an organization requires a particular PDF editor to generate compatible annotation appearances, use that approved workflow. Printing to a new PDF may visually flatten permitted content, but it can remove editable annotations, forms, links, accessibility information, and other features. Do not use printing or conversion to evade document restrictions.

3.4 Know when external components are irrelevant

Ghostscript, printer drivers, codecs, and conversion utilities can matter when converting, printing, or rendering certain non-PDF inputs. They are not the first suspects when an ordinary PDF annotation disappears after reopening. Do not install codecs or Ghostscript solely for this symptom unless your workflow explicitly uses PostScript, conversion, or a related external tool.

If annotations vanish only after printing or conversion, test the original PDF before that external step. A new PDF produced by a virtual printer is a separate document, not the same annotated source file. Success means annotations survive in the source file before any export or print workflow occurs.

4. Inspect or Reset SumatraPDF-settings.txt Safely

SumatraPDF stores application preferences in a file named SumatraPDF-settings.txt. This settings file can affect application behavior and whether preferences persist, but it should not be mistaken for a backup of unsaved PDF annotations. Resetting it cannot restore annotations that were discarded or written to another file.

4.1 Find the settings file for the mode you use

An installed copy commonly keeps user settings under the local application data area for the Windows account. A portable copy may keep its settings beside the executable, depending on how it is run and whether that directory is writable. This distinction matters because users sometimes modify one settings file while launching a different installed or portable executable.

Use Windows search to locate SumatraPDF-settings.txt, then compare its folder and modified time with the SumatraPDF executable you are actually launching. If multiple copies exist, do not delete all of them. First determine whether a desktop shortcut, taskbar shortcut, file association, or portable launcher points to a different executable.

4.2 Back up before editing or resetting

1. Close every SumatraPDF window.
2. Copy SumatraPDF-settings.txt to a safe backup location.
3. Rename the active file to something such as SumatraPDF-settings-backup.txt.
4. Start SumatraPDF and allow it to create fresh defaults if applicable.
5. Repeat the local annotation persistence test.

Close the application before changing the settings file because a running process may write its current preferences when it exits. Avoid pasting undocumented settings from random forum posts. There is usually no reason to hand-edit advanced options until the simple save, path, permission, and cross-viewer tests have been completed.

If a fresh settings file changes nothing, restore the backup if you want your previous preferences. At that point, stop resetting settings and return to file-level causes. If a fresh file fixes the behavior, reapply only the preferences you need and retest periodically to identify the relevant change.

5. Run a Clean Temporary Test Before Reinstalling

Reinstallation is often ineffective because it does not resolve an unwritable PDF, an incorrect path, a cloud conflict, or annotations that were never saved. A clean temporary test provides stronger evidence.

1. Close all PDF viewers.
2. Create a new local test folder with a unique name.
3. Place one ordinary, unrestricted PDF in it.
4. Confirm the file is not read-only.
5. Open it from inside SumatraPDF rather than through a browser or email application.
6. Add one clearly visible annotation.
7. Save, close, and verify the modified time.
8. Reopen the file from the same path in SumatraPDF.
9. Open the identical path in another PDF viewer.

If both viewers display the annotation, SumatraPDF's basic save workflow is working. Stop changing application settings and compare the failing document's permissions, location, annotation type, and sync history with the successful test.

If the annotation appears in SumatraPDF but not in the other viewer, focus on compatibility and the annotation's visual appearance. If it appears nowhere and the modified time never changes, focus on save commands and write access. If the modified time changes but neither viewer shows the annotation, preserve both the before and after files and test with another simple PDF before considering a reinstall.

Only reinstall after you have confirmed that multiple local, writable PDFs fail under a clean configuration. Download software from the official project source, and keep backups of settings and test documents. Remember that reinstalling cannot recover discarded annotations.

6. Quick Fix Checklist

• Use Save or Save As before closing the annotated PDF.
• Respond to any save prompt instead of discarding changes.
• Verify the full path, filename, size, and modified time.
• Confirm that you reopened the edited copy rather than an attachment or duplicate.
• Check which application Windows uses when you double-click a PDF.
• Copy cloud-hosted or network-hosted files to a local writable folder for testing.
• Check the Read-only attribute and your folder permissions.
• Respect PDF permissions and request an editable copy when required.
• Test the identical file in another PDF viewer.
• Remember that non-PDF formats do not necessarily store PDF annotations.
• Back up SumatraPDF-settings.txt before resetting it.
• Use a clean local test before reinstalling software.

Stop troubleshooting as soon as a saved annotation survives reopening in the same file and appears in the viewer required by your workflow. Additional resets or conversions can introduce new variables and make the original cause harder to identify.

7. Frequently Asked Questions

7.1 Can SumatraPDF recover annotations that I discarded?

Not from an unchanged PDF. If you selected an option that discarded changes or closed without successfully saving, the edits may never have been written to the document. Check cloud version history, Windows backups, File History, or your organization's document-management system for an earlier edited copy. Do not reset settings or reinstall in the expectation that unsaved annotations will reappear.

7.2 Why do annotations appear in SumatraPDF but not another viewer?

The viewers may interpret the annotation type or its visual appearance differently. Confirm that both applications opened the exact same path, then test a simple highlight or note in a local copy. For shared documents, verify compatibility in the recipient's required viewer before distributing the file.

7.3 Why are annotations missing only from files in OneDrive or another cloud folder?

A synchronization conflict, incomplete upload, file lock, or older remote version may have replaced the edited copy. Close the file on other devices and test a local copy outside the synchronized folder. If that works, inspect the service's sync status, conflict files, and version history.

7.4 Will deleting SumatraPDF-settings.txt restore my annotations?

No. The settings file stores application preferences, not a guaranteed backup of discarded PDF edits. A safe reset may help diagnose unusual application behavior, but it cannot add annotations back to a PDF that was never saved. Always back up the settings file before resetting it.

7.5 Does reinstalling SumatraPDF fix missing annotations?

Usually not when the cause is an unsaved edit, a read-only file, a different copy, PDF permissions, or cloud replacement. Reinstall only after several ordinary local PDFs fail the controlled save-and-reopen test with a clean configuration.

7.6 What is the clearest sign that the problem is fixed?

Add a test annotation to a local writable PDF, save it, confirm the file's modified time changes, close the application, and reopen the same path. Then verify the annotation in SumatraPDF and, if cross-viewer visibility matters, in the recipient's viewer. If it survives both checks, stop changing settings and use that successful workflow as the baseline.