Where are FSX log files and how do I diagnose problems?

FSX and FSX: Steam Edition do not create one master troubleshooting log. Flight history is stored as Logbook.BIN in the simulator’s Documents folder, while crash details are recorded by Windows Reliability Monitor and Event Viewer. Use the Windows records to identify the faulting module; treat Logbook.BIN as data, not a readable text log.

Which FSX log files contain useful diagnostic information?

The useful record depends on whether you are investigating a crash, damaged flight history or a SimConnect add-on.

The Documents location can be redirected to OneDrive or another drive. A Steam Edition installation may use Flight Simulator X - Steam Edition Files, particularly when boxed FSX and Steam Edition coexist. Likewise, Steam Edition may use either the legacy FSX AppData folder or an FSX-SE folder.

Paste %APPDATA%\Microsoft into the Windows Run box to bypass hidden-folder settings. If there are two FSX folders, check which one has files whose modification dates change when you close the simulator.

How do I diagnose an FSX crash with Windows logs?

Reliability Monitor is usually the quickest way to find the Windows crash record associated with fsx.exe.

1. Reproduce the failure once. Record the time, aircraft, airport, weather and exact action that preceded it.
2. Open Reliability Monitor. Search Windows for View reliability history, select the red failure marker and open its technical details.
3. Record the important fields. Note the faulting application, faulting module, exception code and application path.
4. Check Event Viewer if more detail is needed. Open Windows Logs, select Application and examine errors at the same timestamp. Entries from Application Error, .NET Runtime or SideBySide can be relevant.
5. Repeat the same test after one controlled change. Use a default aircraft, remove the suspect add-on or try a different airport. Changing several things together destroys the comparison.

What does the faulting module mean?

The faulting module identifies where Windows detected the crash, which is not always the component that caused it.

• A named add-on DLL or gauge is a strong lead. Disable that component using its installer or configuration entry, then repeat the same flight.
• A core Windows module such as ntdll.dll or KERNELBASE.dll is usually only the point where the failure surfaced. Do not replace Windows files based on that name alone.
• An FSX graphics or terrain module should be matched to the circumstances. A crash at one airport suggests scenery or AI content; a crash only with one aircraft points towards its panel, gauges, model or textures.
• Exception code 0xc0000005 means an access violation. It describes the type of failure but does not identify the guilty add-on.
• An out-of-memory message takes priority over a generic module name. FSX is a 32-bit application, so high-resolution scenery and complex aircraft can exhaust its available address space even when Windows still has free RAM.

If the record remains inconclusive, follow our step-by-step FSX crash-isolation checklist to reset the configuration safely and test add-ons without dismantling the entire installation.

Can a corrupt Logbook.BIN stop FSX working?

A damaged Logbook.BIN can prevent FSX from opening normally, crash the logbook screen or make flight history disappear.

1. Close FSX completely.
2. Open the simulator’s Documents folder. Find Logbook.BIN in the applicable Flight Simulator X files folder.
3. Make a backup copy. Do not edit the binary file in Notepad or another text editor.
4. Rename it temporarily. Use a name such as Logbook.old, making sure Windows has not hidden the real file extension.
5. Start FSX again. The simulator should create a fresh logbook. If the problem disappears, the original file was probably corrupt; if nothing changes, restore the backup.

Renaming the file does not erase the backup, but its flights will not appear while FSX is using the new logbook. To try salvaging the history, use the utility designed to recover data from a damaged FSX logbook.

How do I create a SimConnect log?

SimConnect logging must be enabled manually and is useful only for programs or gauges that communicate with FSX through SimConnect.

1. Close FSX and create a writable log folder. Avoid protected locations such as Program Files.
2. Create SimConnect.ini. Save it in the same Documents files folder used by FSX. Confirm that Windows has not silently named it SimConnect.ini.txt.
3. Add the logging settings. Put [SimConnect], level=verbose and file=C:\your-writable-folder\SimConnect%03u.log on separate lines. The optional line file_max_index=9 limits the rolling file index.
4. Run one short test. Start the add-on, reproduce the connection problem and close FSX before reading the output.
5. Disable verbose logging afterwards. Rename or remove SimConnect.ini so repeated sessions do not keep generating diagnostic files.

Look for the client’s connection, the point at which messages stop and any reported exception near the failure. Routine connection and dispatch entries are not errors. If the add-on crashes before it connects to SimConnect, the trace may contain nothing useful; return to Reliability Monitor and the add-on-loading entries in dll.xml or exe.xml.

What if FSX creates no useful error record?

No useful record usually means the problem must be isolated by context rather than by a single log entry.

• If the failure occurs with one aircraft, test a default aircraft in the same place and weather.
• If it occurs at one airport, disable the newest local scenery or AI package first.
• If it began after a configuration change, back up and rename fsx.cfg so FSX can generate a clean copy.
• If it occurs during add-on loading, inspect dll.xml and exe.xml for the named component, malformed XML or an obsolete path.
• If FSX freezes rather than crashes, wait briefly before forcing it closed; a forced termination may produce only a generic Windows entry with no original cause.

The mistake we see most often is treating Logbook.BIN as the FSX crash log. For ordinary crashes, Windows Reliability Monitor and Event Viewer are the primary evidence; the logbook and SimConnect trace answer narrower, separate questions.