SumatraPDF Annotations Not Saving: How to Fix It

If SumatraPDF annotations are not saving, the problem usually falls into one of four categories: the annotation changes were not explicitly saved, the PDF cannot be written to its current location, the document restricts changes, or SumatraPDF is reopening a different copy of the file. Cloud synchronization, portable-mode permissions, and a damaged settings file can also contribute. The steps below focus specifically on PDF highlights, underlines, strikeouts, comments, and other annotations, not favorites or bookmarks.

1. Confirm the Symptom With a Simple Local PDF Test

Before changing settings or reinstalling anything, determine whether the failure affects every PDF or only one document. A controlled test prevents you from troubleshooting SumatraPDF when the real problem is a protected file, a cloud folder, or an unsupported document format.

1.1 Create a controlled test file

1. Choose a small, nonconfidential PDF that you are allowed to modify.
2. Copy it to a simple local folder such as your Windows Documents folder.
3. Rename the copy to something obvious, such as annotation-test.pdf.
4. Open that exact copy in SumatraPDF.
5. Add a clearly visible annotation, such as a highlight or text comment.
6. Use SumatraPDF's save command before closing the document. If prompted to choose a destination, save to a new filename in the same local folder.
7. Close SumatraPDF completely, reopen the saved file, and inspect the annotated page.

Success means the annotation remains visible after the application has been closed and the saved PDF has been reopened. If this works, stop changing global settings. SumatraPDF can save annotations, and the original file or its location is the likely cause.

If the annotation disappears from the controlled test too, continue with the workflow and settings checks below.

1.2 Make sure the file is actually a PDF

SumatraPDF can read several formats, including eBooks, comics, CHM, DjVu, XPS, and images. PDF annotation editing does not automatically apply to every format the program can display. Confirm that the file has a .pdf extension and is identified as a PDF in Windows properties.

If you are viewing an EPUB, MOBI, CBZ, CBR, DjVu, XPS, CHM, or image file, do not assume that a mark shown temporarily in the interface can be embedded into that source format. Test with a genuine PDF before treating the behavior as a broken annotation feature.

2. Check the Annotation Editing and Saving Workflow

Creating an annotation and saving the changed PDF are separate actions. The mark may appear during the current session even though the underlying file has not yet been updated.

2.1 Finish the annotation edit

After adding or changing an annotation, finish the edit before closing the window. For example, confirm text entered into a comment and click outside the active annotation field. An unfinished edit may not be committed to the document state that SumatraPDF saves.

Next, use the available save command in SumatraPDF. Depending on the situation, SumatraPDF may save the PDF directly or ask for a destination. Pay attention to the filename and folder in the save dialog. Saving a modified copy elsewhere and later reopening the original file can look exactly like data loss.

2.2 Do not choose to discard changes

If SumatraPDF asks whether to save changes when you close the PDF or exit the application, choose the option that saves them. Choosing a discard or do-not-save option removes the unsaved annotation edits from that session.

After saving, close the PDF and reopen it from the destination shown in the save operation. Do not rely solely on a recent-files entry until you have verified the full path.

2.3 Verify which copy Windows opens

A Windows file association controls which application opens a PDF, but it does not normally control whether annotations can be stored. It can still create confusion if double-clicking a file opens another viewer, a browser preview, or a different copy downloaded from email.

In File Explorer, locate the saved PDF and open it deliberately. Check its folder, filename, modified date, and file size. If needed, use Open with and select SumatraPDF for this test. Success means the deliberately opened file contains the annotation and has an updated modification time.

3. Check the File, Folder, and PDF Permissions

If the local test succeeds but the original PDF fails, concentrate on the source document and its storage location. Reinstalling SumatraPDF is unlikely to repair a file that Windows or the PDF itself does not permit the application to change.

3.1 Remove Windows read-only obstacles safely

Right-click the PDF in File Explorer, select Properties, and inspect its attributes and security access. If the file is read-only and you are authorized to modify it, clear the read-only attribute or save an annotated copy to a writable folder.

Files in protected locations can also resist direct modification. Examples include application installation directories, some shared network folders, read-only removable media, and folders where your Windows account lacks write permission. Do not weaken system-wide security settings merely to edit one document. Copy the PDF to Documents, annotate the copy, and save it there.

Success means the copied PDF can be saved, its modified date changes, and its annotation survives reopening. At that point, stop changing SumatraPDF settings and address access to the original folder only if necessary.

3.2 Respect PDF document restrictions

A PDF can include permissions that restrict modification or annotation. If the document owner has disabled changes, use an authorized editable copy or ask the owner for one. Do not attempt to bypass document security, passwords, DRM, or permission controls.

To isolate this issue, compare the restricted document with the simple local test PDF. If only the restricted document fails, the appropriate fix is obtaining permission or using a permitted review workflow, not resetting the reader.

3.3 Test outside cloud and network folders

OneDrive, Dropbox, Google Drive, enterprise synchronization software, network shares, and document-management systems may upload, replace, lock, or version a PDF while it is open. Another computer or collaborator may also overwrite your edited copy.

1. Close the PDF on other devices and in other applications.
2. Copy it from the synchronized or network folder to a local folder.
3. Add one test annotation and save under a new filename.
4. Close and reopen the local file.
5. If successful, copy the finished file back only after confirming synchronization is idle.

If the local copy retains the annotation, SumatraPDF's annotation feature is working. Investigate synchronization conflicts, duplicate filenames, file locking, or version restoration in the relevant cloud service instead of reinstalling the reader.

3.4 Close other programs using the PDF

A browser, email preview pane, indexing tool, backup utility, PDF editor, or another SumatraPDF window may have the file open. Close other viewers and disable File Explorer's preview pane temporarily. Then reopen the local copy, make one annotation, and save it.

Printer drivers, Ghostscript, and media codecs are generally unrelated to saving ordinary PDF annotations. They become relevant only when the actual symptom involves printing, PostScript conversion, or rendering a specialized format. Do not replace drivers or install Ghostscript solely because a PDF comment was not retained.

4. Check the Annotation in Another PDF Viewer

Sometimes an annotation is present in the PDF but is not rendered as expected by a particular viewer. Cross-checking helps distinguish a saving failure from a display or compatibility problem.

1. Make a backup of the PDF before testing it in multiple applications.
2. Save a new annotation in SumatraPDF.
3. Close SumatraPDF so that no unsaved session remains.
4. Open the saved file in another reputable PDF viewer that supports standard PDF annotations.
5. Look at the exact page and annotation location.

If the annotation appears in the other viewer, the PDF contains it. Reopen the same path in SumatraPDF and check whether you are seeing an older tab, cached cloud copy, or different filename. If neither viewer can see the annotation after SumatraPDF closes, focus on saving and write permissions.

If the annotation appears differently between viewers, preserve the original and test a simple annotation type such as a basic highlight or text note. Complex appearance data can be interpreted differently across PDF software. For an important review process, confirm that recipients can see the saved marks in the viewer they use.

5. Inspect SumatraPDF-settings.txt Safely

SumatraPDF stores application preferences in a text settings file. A settings-persistence problem is more likely when ordinary preferences also reset between launches, not when one protected PDF alone rejects annotations.

5.1 Locate the relevant settings file

An installed copy commonly stores user data under the current Windows user's local application-data area. A portable copy may keep its settings with the portable program files. The exact active location depends on how SumatraPDF was launched, so avoid editing every similarly named file you find.

Close all SumatraPDF windows before inspecting SumatraPDF-settings.txt. Make a backup copy first. Open the file only with a plain-text editor, and do not copy untrusted settings content into it.

5.2 Check whether settings persist

Change one harmless visible preference in SumatraPDF, close the program normally, and reopen it. If that preference remains, settings persistence is probably working. Do not reset the settings file merely because annotations in one PDF failed to save.

If preferences repeatedly revert, check whether the settings file or its containing folder is read-only, whether security software is blocking writes, or whether a portable copy is running from a protected folder such as Program Files. Move a portable copy to a user-writable folder for testing rather than changing broad Windows permissions.

5.3 Reset without destroying the original

If multiple preferences fail to persist or the settings file appears damaged, close SumatraPDF and rename the active file to SumatraPDF-settings.backup.txt. Do not delete it. Start SumatraPDF and allow it to create fresh settings, then repeat the local annotation test.

Success means a fresh settings file is created, preferences survive a restart, and the test PDF retains its annotation. If annotations still fail while preferences save correctly, restore your backup if desired and continue investigating the PDF path or application build. A settings reset is not a substitute for document write access.

6. Run a Clean Temporary Test Before Reinstalling

A clean test separates installation problems from document problems without immediately deleting preferences. Back up important PDFs and your settings file first.

1. Download SumatraPDF only from its official website.
2. Place a portable copy in a new, writable folder under your user profile.
3. Do not copy old settings into the test folder.
4. Copy a simple PDF into another local writable folder.
5. Open that PDF from the clean SumatraPDF instance.
6. Add one annotation, save it under a new name, close the program, and reopen the saved file.

If the clean test works, the original installation environment, active settings, launch method, or file location is responsible. Change one factor at a time until the failure returns. Stop as soon as you identify the cause.

If the clean test fails, confirm that you downloaded an official current release, that the file is a real PDF, and that another viewer can write to the same test copy. Reinstalling may be reasonable only after these checks. Repeated reinstalls will not solve PDF restrictions, cloud replacement, or a read-only destination.

7. Quick Fix Checklist

• Back up important PDFs before adding or changing annotations.
• Test a genuine PDF copied to a local writable folder.
• Complete the annotation edit and explicitly save before closing.
• Read close prompts carefully and do not discard changes.
• Confirm the exact filename and destination used during saving.
• Check the file's modified date after a successful save.
• Use a new filename if the original cannot be overwritten.
• Respect PDF permissions and request an authorized editable copy when necessary.
• Pause cloud conflicts by testing outside synchronized and network folders.
• Close browsers, preview panes, editors, and other programs using the PDF.
• Open the saved PDF in another viewer to confirm the annotation exists.
• Reset SumatraPDF-settings.txt only if settings themselves do not persist.
• Run a clean portable test before reinstalling the application.

8. Frequently Asked Questions

8.1 Why can I see a highlight until I close SumatraPDF?

The highlight exists in the current session, but the changed PDF may not have been saved. Finish the edit, use the save command, confirm the destination, and choose to save rather than discard changes when closing. Then reopen that exact file.

8.2 Why do annotations save in one PDF but not another?

The failing PDF may be read-only, stored in a protected or synchronized folder, restricted by document permissions, open in another program, or structurally incompatible with the attempted change. Copy it locally and compare it with a simple editable test PDF. If only one document fails, stop resetting global preferences.

8.3 Can SumatraPDF save annotations in EPUB, DjVu, XPS, or comic files?

Do not assume that PDF annotation behavior applies to every format SumatraPDF can read. This troubleshooting process concerns annotations embedded in PDF files. If the source is another format, verify that the format and application explicitly support saving the type of mark you need.

8.4 Does portable mode prevent annotation saving?

Portable mode does not inherently prevent saving, but the program and settings must be in locations your Windows account can write to. A portable copy launched from protected media or a restricted folder may not persist its settings. The target PDF must also be writable independently of the application folder.

8.5 Should I delete SumatraPDF-settings.txt?

Not as a first step. Rename and preserve the file only when application preferences also fail to survive a restart or a clean test points to configuration damage. A settings reset will not unlock a read-only PDF or resolve a cloud synchronization conflict.

8.6 When should I stop troubleshooting?

Stop changing settings once a saved annotation survives closing and reopening the intended PDF. If a local test works, focus only on the original document or location. If another viewer confirms the annotation exists, focus on display or file-selection differences. Once the cause is isolated, avoid unrelated changes to codecs, printer drivers, Ghostscript, or Windows security.