Why does Prepar3D v5 freeze, and how do I fix it?

Prepar3D v5 usually freezes when an incompatible add-on, corrupt configuration or shader cache, faulty scenery, graphics-driver failure, or exhausted VRAM stalls its main or renderer process. Reproduce the problem with a default aircraft and airport, disable add-ons, rebuild generated files, reduce graphics load, then repair Prepar3D only if that clean baseline still hangs.

What usually causes Prepar3D v5 lock-ups?

The point at which Prepar3D v5 stops responding is often the best clue. A freeze tied to one aircraft or location usually implicates an add-on, while a lock-up after a long flight points more towards resource pressure, a driver fault or an add-on leaking memory.

How do I fix Prepar3D v5 freezing?

The reliable method is to establish a repeatable clean baseline, then restore components until the hang returns. Changing several unrelated settings at once may hide the symptom without identifying its cause.

1. Confirm that Prepar3D is actually frozen. Wait several minutes once and inspect CPU and disk activity in Task Manager. The first launch after rebuilding shaders or loading complex scenery can appear unresponsive; repeated failure at the same point is much stronger evidence of a fault.
2. Start a fresh default scenario. Use a default aircraft, a simple default airport, fair weather and no saved scenario. Disconnect optional weather, traffic and camera utilities first, because a default aircraft is not a clean test while global add-ons remain active.
3. Determine whether it hung or crashed. Check Reliability Monitor and Event Viewer under Windows Logs > Application. If Prepar3D.exe closed rather than remaining in Task Manager, use our process for separating a Prepar3D crash from a hang and interpreting its event record.
4. Disable add-ons by category. Stop external SimConnect clients, then disable third-party aircraft, airports, regional scenery and global enhancements. With a large library, disable half the suspect packages, test, and keep halving the failing group. Restart Prepar3D after each activation change because an in-process module can remain loaded until the simulator exits.
5. Rebuild generated files separately. Close Prepar3D and rename %APPDATA%\Lockheed Martin\Prepar3D v5\Prepar3D.cfg to a backup name. Test before also renaming the Shaders folder under %LOCALAPPDATA%\Lockheed Martin\Prepar3D v5. Prepar3D creates replacements at launch; the first shader rebuild may take longer than normal. Reapply settings manually rather than copying the entire old configuration back.
6. Test location-specific scenery. If the freeze occurs near the same coordinates, disable the airport and any overlapping regional scenery, terrain mesh, vector or landclass package. Disabling only the visible airport is a common mistake because another package may supply the conflicting data.
7. Reduce graphics and traffic load. Prepar3D v5 uses DirectX 12 and can place heavy demands on dedicated GPU memory. Lower texture resolution, anti-aliasing, shadows, dynamic reflections, cloud distance, autogen and traffic, then repeat the same scenario. Our practical Prepar3D performance settings identify the adjustments with the greatest effect.
8. Repair only after the clean baseline fails. Use the installer matching the installed Prepar3D v5 build, and do not mix Client, Content or Scenery components from different builds. A clean graphics-driver installation is also justified if default scenarios fail; if the trouble began immediately after a driver change, compare it with the previously stable driver.

Do not delete aircraft, gauge, effect or scenery folders at random. Older installers may have copied files directly into Prepar3D's core folders, while newer package-based add-ons can be activated from more than one location. Disabling one package does not remove a second copy left by an earlier installation.

Does “Not responding” mean Prepar3D has crashed?

“Not responding” means Windows is not receiving timely messages from Prepar3D's main process; it does not prove that the process has crashed. Active CPU or disk use during a one-off load can justify waiting, but a repeatable hang at the same aircraft, airport or menu action needs isolation.

If audio continues while the picture remains fixed, focus on the graphics driver, overlays, display mode and VRAM. If the audio loops and all simulator input stops, an in-process add-on, scenery operation or main-thread stall is more likely.

What does “renderer process has crashed” mean?

The message renderer process has crashed does not automatically mean Prepar3D's DirectX renderer failed. It can come from an add-on's embedded web interface, electronic flight bag, launcher or other helper process.

• If the Windows report names Prepar3D.exe, test the graphics driver, VRAM load, shaders and overlays.
• If it names a separate helper executable, disable or repair the add-on that owns that process before reinstalling Prepar3D.
• If the display turns black but Prepar3D remains open, follow our black-screen checks for shaders, GPU selection, drivers and display settings.
• If the display driver recovers and Prepar3D then closes, treat the incident as a GPU or driver crash rather than a normal application hang.

How do I check memory use and add-ons?

Checking memory is useful only when you compare the same scenario with and without the suspect add-on. A single high reading does not prove a leak because Prepar3D and Windows both retain cached data.

1. Record a baseline. Start a simple default scenario and note the memory used by Prepar3D.exe, any external add-on processes, total committed memory and dedicated GPU memory.
2. Repeat the failing route. Watch for memory that climbs steadily as the freeze approaches. An external weather, traffic or avionics process must be monitored separately from Prepar3D.
3. Disable one suspect category. Repeat the same route for at least as long as the original flight. If the growth and freeze disappear together, narrow that category using the half-and-half method.
4. Interpret in-process add-ons correctly. Memory allocated by a DLL, gauge or scenery component loaded inside Prepar3D appears under Prepar3D.exe; Task Manager cannot identify that component by name.

Prepar3D v5 is a 64-bit application, so this is not the old FSX 4 GB address-space problem. It can still exhaust physical RAM, committed memory or dedicated VRAM. Keep the Windows page file system-managed unless you have a specific reason to change it, and use our CPU, GPU and VRAM diagnosis to decide which settings should be lowered.

What does the Windows error report actually tell me?

A Windows report identifies the process and failure type, but it rarely names the offending add-on directly. Generic modules such as ntdll.dll or KERNELBASE.dll are where a failure surfaced, not proof that Windows caused it.

If you searched for diskuse k report, meaning a discussion of a report, these are the details that make the report useful:

• The exact time of the incident and whether Prepar3D closed, remained open or required a PC restart.
• The faulting application, faulting module, exception code or application-hang signature.
• Any nearby display-driver or hardware warnings in the Windows System log.
• The aircraft, airport, weather source, route stage and last action before the freeze.
• Whether the same scenario works with default content and external utilities stopped.

Remove personal folder names and licence information before sharing a report. If the computer hard-locked, there may be no application event because Windows had no opportunity to write one; that absence itself shifts suspicion towards the driver or hardware.

What if none of that helped?

If every test produces no change — “none of that helped”, Portuguese não resolveu nada or nao resolveu nada, or Dutch nee — stop repeating random setting changes. The next tests must separate per-user files, background software, the Prepar3D installation and the PC.

1. Test from a fresh Windows user profile. This creates new per-user Prepar3D configuration files and can exclude add-ons registered only for the original user. If it works there, the base installation is probably sound.
2. Use a clean Windows startup. Leave Microsoft and essential driver services active, but prevent optional overlays, monitoring tools and simulator utilities from loading. A successful test implicates background software rather than Prepar3D scenery or aircraft.
3. Repair the matching Prepar3D components. Test again before restoring add-ons. Repairing the simulator does not necessarily remove damaged per-user files or third-party packages, which is why the clean tests come first.
4. Test the PC at stock settings. Remove CPU and GPU overclocks, undervolts and aggressive memory profiles. Check temperatures and Windows hardware-error records during the same repeatable scenario.

A full reinstall is the last resort. Uninstalling Prepar3D may leave user configuration and add-on packages behind, so immediately restoring the old folders can reproduce the freeze on a fresh installation. Prove that the unmodified simulator works before adding anything back.

What if the entire PC freezes?

A system-wide lock-up is more likely to involve the display driver, unstable CPU or memory settings, heat or failing hardware than Prepar3D alone. Return all tuning to stock, remove overlays, check temperatures and inspect the Windows System log for display-driver recovery or hardware-error entries after restarting.

A successful desktop session does not prove an overclock or undervolt is stable. Prepar3D can sustain combined CPU, GPU and memory load for long periods, exposing instability that lighter applications never trigger.