How do I fix a logbook error when exiting FS2004?

To fix a logbook error when exiting Microsoft Flight Simulator 2004 (FS2004/FS9), close the simulator, back up FS9.CFG and any existing Logbook.BIN, then correct the [LOGBOOK] path. If the path is writable but the error remains, rename Logbook.BIN and let FS2004 create a clean replacement.

What causes the FS2004 logbook error on exit?

The error means FS2004 cannot find, read or update its logbook when ending a flight or closing the simulator. The usual causes are an obsolete path in FS9.CFG, a damaged logbook or Windows blocking write access.

The standard FS2004 logbook is Logbook.BIN, not logbook.log. Despite the name, it is a binary file and must not be edited as ordinary text.

• FS9.CFG was copied from another PC or Windows account and still names the old user profile.
• The Documents folder was moved or redirected, but LOG_FILE still points to its former location.
• Logbook.BIN became corrupt after a crash or interrupted shutdown.
• The file or configuration is read-only, or Windows security is preventing fs9.exe from writing to the folder.
• FS2004 was running while FS9.CFG was edited, so it replaced the change on exit.

How do I correct the LOG_FILE entry in FS9.CFG?

Correcting the logbook path is the first fix to try because it preserves your existing flight history.

1. Close FS2004 completely. Confirm that fs9.exe is no longer running before changing either file.
2. Locate the active FS9.CFG. Press Windows key + R, enter %APPDATA%\Microsoft\FS9, and open FS9.CFG with a plain-text editor. This is the per-user configuration folder, not the FS2004 installation directory. Turn on filename extensions in File Explorer so you do not accidentally create FS9.CFG.txt.
3. Back up the configuration. Copy FS9.CFG to a safe location. Find its [LOGBOOK] section and read the line beginning LOG_FILE=. If the referenced Logbook.BIN exists, back that up as well.
4. Check the recorded location. Look for an old account name, an obsolete Documents and Settings path, a missing folder or a Documents path that no longer matches the one used by Windows. Try creating and deleting a small text file in the target folder; if that fails, FS2004 will not be able to update its logbook there.
5. Enter the correct full path. On a non-redirected Windows profile, a typical entry looks like this:

[LOGBOOK]

LOG_FILE=C:\Users\YourName\Documents\Flight Simulator Files\Logbook.BIN

Replace YourName and the rest of the example with the real location on your PC. If Documents is redirected into OneDrive or another local folder, use the path shown by Windows rather than assuming the example is correct.

The entry must name the file, not just its folder. Do not add quotation marks, leave the placeholder account name, use an environment variable such as %USERPROFILE%, or retain two active LOG_FILE lines.

1. Use a simpler location if necessary. Create a user-owned folder such as C:\Users\YourName\FS9Data, then set the line to LOG_FILE=C:\Users\YourName\FS9Data\Logbook.BIN. Avoid placing it in the FS2004 installation folder under Program Files.
2. Save and test. Start FS2004, complete or end a brief flight, and close the simulator normally. Check that the error has gone and that the timestamp on Logbook.BIN has changed.

Which logbook fix matches the symptom?

The result of testing with a corrected path or a fresh logbook identifies which part has failed.

What should I do if Logbook.BIN is corrupt?

A corrupt Logbook.BIN must be moved aside so FS2004 can create a valid replacement.

1. Close FS2004 and preserve the old file. Copy it somewhere safe, then rename the original to Logbook.BIN.old.
2. Start FS2004 and record a test flight. End the flight and exit normally so the simulator has an opportunity to create and update a new Logbook.BIN.
3. Check the result. If the fresh file works, the original was corrupt. If no replacement appears, return to the path and permission checks because corruption was not the only problem.

Your old flight history will not appear in the replacement file. Do not open the backup in a text editor or overwrite the working file with it; our guidance on backing up, replacing and testing an FS2004 Logbook.BIN file covers the recovery choices in more detail.

Why does the logbook error return on Windows 10 or 11?

A recurring error usually means FS2004 still lacks reliable write access to the selected file or folder.

Check that FS9.CFG and Logbook.BIN are not read-only. If you can manually create a file in the folder but FS2004 cannot, Windows security protection may be blocking fs9.exe; allow the simulator through the relevant protection rather than disabling security globally.

Running FS2004 once as administrator may disguise a permissions problem, but it is not the best permanent fix. A writable folder inside your normal user profile is cleaner and avoids producing different behaviour between elevated and ordinary launches. Our FS2004 guidance for Windows 10 and 11 explains the related profile, permissions and configuration issues.

Is a Flight Editor error the same as this logbook error?

No: an error opening or saving a flight is a different fault unless the message or shutdown behaviour specifically points to the logbook.

FS2004 saved flights use files such as .FLT, while flight plans commonly use .PLN; neither is Logbook.BIN. Apply this logbook fix when the error names the logbook, occurs as FS2004 records a flight, or appears when the simulator exits. If the error occurs only while an editor or add-on loads a flight, preserve the exact message and named file rather than deleting the logbook.

Should I rebuild FS9.CFG?

Rebuild FS9.CFG only after correcting the path, testing a fresh logbook and ruling out folder permissions.

With FS2004 closed, rename the active file to FS9.CFG.old, then start the simulator and allow it to generate a default configuration. This resets simulator preferences, so keep the backup and do not immediately copy the entire old configuration over the new one—the faulty [LOGBOOK] entry may come with it.

If FS2004 also fails before reaching the main screen, follow our FS9.CFG rebuild and startup-crash checks before restoring settings selectively.