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Known Issues & Self Help

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Kerbal Space Program: Known Issues & Self Help

For help with modded versions of KSP, please check the Modded Support Forum

Click here!

KSP can change considerably during each update. However, there are a handful of known specific issues that can cause crashes, many of which can be fixed easily.

This thread is broken up by Operating System (Linux, Windows, and Mac). Some issues are operating system specific, while others can apply to all versions (cross platform). Additionally, each operating system section links to a thread which contains many of the most current Operating System specific issues and fixes. Please also check those threads to see if your issue is already listed. If you can't find help here for your problem, please read the Support Support & Bug Report Guide for details on how to post information about your issue.

General Tips to keep KSP Healthy

When installing or updating KSP, please keep the following tips in mind:

  • Keep a copy of your old (presumably working) KSP install. This will ensure your old working copy isn't messed up in the upgrade process and keeps a copy of your existing save games in case a bug destroys your files.
  • Unzip/install KSP into a new (empty) directory and do not merge the files with your old install. Many files change during KSP updates, and sometimes merging files creates a mess. It's best to start with a fresh install. This will also ensure you still have a "working" copy of KSP should you encounter problems with the new version.
  • Let KSP create a new "settings.cfg" file rather than copying over your old one. Sometimes using old ones introduces strange behavior, especially when new settings are added.
  • Mods: If you use mods, make sure to download updated mods for the new version of KSP. Using outdated mods can cause crashes, graphics problems, system slowdown, and other glitches.
  • Add any mods one (or a few) at a time if practical. Doing so will make it easier to spot glitches or bugs with KSP and any mod conflicts. If you encounter an unusual problem, try removing some of the mods and see if that helps. This will help narrow down the problem to a specific mod combination for requesting help.

General Issues

In addition to the below, please see here for Cross-Platform Bugs and Possible Fixes.

Purchasing, Installing and Updating

I bought the game but I cannot download it from the store

Most likely something has gone wrong during the payment process. Please send an email to [email protected] with your payment details so that the purchase can be verified manually.

My Steam transfer didn't work

Please send an email to [email protected] with your details. This issue cannot be resolved here.

I understood that KSP runs on Unity 5 now, which supports 64 bit builds. Where can I download the 64-bit version?

The 64bit binary is in the Kerbal Space Program folder.

My download is corrupt or doesn't show up

The download may have failed to download properly due to download managers, or an antivirus program may have interfered. Please try to disable these programs for a short while and try again. If the problem persists try downloading it on another computer or on a different internet connection. Google Chrome is known to corrupt the KSP download for unknown reasons.

KSP does not install properly

Your antivirus program may be interfering or you do not have the permissions to unzip the KSP file. Please try disabling the antivirus software, install KSP to a directory such as C:\Games or C:\KSP if you're using Windows and doublecheck that the folder is not set as 'read only' (which sometimes happens with the Steam version). On Windows you may also try to log into an administrator account to fix this issue.

I lost my password to the store and resetting it doesn't work

We have realized that some email providers (Verizon, sbcglobal.net, freenet.de, etc.) have blocked our domain (kerbalspaceprogram.com) and IP Address due to their strict incoming email rules. They added us to their spam lists, so you won't receive any email from us. Send an email to KSP Support explaining your problem. They will reset manually your password and ask you to change your KSP Store Account email address.

I just upgraded to the latest KSP and it's running really slowly or not at all

If this happens make sure that all mods you're using have been updated to run on the latest version. If you're unsure about this start with a completely fresh install of KSP and start adding mods back one by one. Old versions of mods are known to cause slowdowns and other issues after an update.

General Computer Issues

System requirements

Kerbal Space Program will put quite some strain on even modern systems. To run KSP you will need at least an Intel Core2Duo or equivalent processor, 2GB of Ram (4 is recommended) and an Intel HD3000 integrated graphics card or better. A dedicated graphics card is highly recommended. If you're unsure about your computer specifications, try lowering the rendering quality in the KSP graphics settings.

Save your memory!

If KSP crashes often you may be running out of memory. Using fewer mods that add parts and closing all other programs while running KSP may end your crashes.

Also, if you are using mods, have more than 4 GB of RAM available, and a 64-bit system you can try running 64-bit version of KSP. Please be advised that the 64-bit version is currently highly experimental and is prone to specific issues and crashes.


Some antivirus brands will interfere with KSP causing it to crash or lag severely. If you're experiencing issues make sure KSP is ignored by your antivirus by putting KSP.exe on your ignore list or whitelist. Also confirm the issues are still present with the antivirus turned off before continuing.

Update your drivers and general computer maintenance

Hardware communicates with your operating system through drivers. New drivers are regularly released by the hardware manufacturers and solve all sorts of problems. Even if this does not solve your problem it may well improve your computer's performance as a whole. A well maintained computer is a stable and fast computer so be sure to clean up your hard disk, uninstall unneeded programs and de-fragment your hard disk.

Additionally, ensure your system is receiving adequate cooling. Because KSP is processor and graphics intensive, some computers may experience overheat related issues if they aren't adequately cooled.

AMD Phenom processor

Phenom CPU's can still crash even with all fixes in this thread applied, this is due to the Phenom's Turbo Core technology which can cause instability in KSP. You can disable Turbo Core in two ways:

  • Add the following line to the target box of a shortcut after KSP.exe: "-force-gfx-st" (without the quotes)
  • Disable it in the Bios / UEFI

Xbox 360 controllers don't work

They need setting up like any other controller before they can be used.

Joystick throttle is stuck between 5% and 95%

KSP has difficulty with some joysticks even if they've been calibrated properly. This is a Unity problem and can't be fixed in KSP at this time.

I observe no re-entry effects or just an orange glow without the flames

This means your graphics card does not (fully) support the shader technology used for these effects. This usually happens on older or integrated graphics cards. If this happens on a modern dedicated graphics card please try updating your drivers and post a thread if the issue persists.

Sound stutters

This is a bug in Unity and it affects some players quite badly and others not at all, though is most common on Windows, there is no known cause or fix at this time.

Physics stutters

The Unity garbage collector pauses the game when the heap memory is full so it can free memory.

Jagged orbit lines

Orbit lines can appear jagged or broken, this is caused by the graphics card applying anti-aliasing system wide.

This can be fixed by disabling any global anti-aliasing in your card settings panel.

The windows in cockpit view aren't transparent, instead they're grey.

This is due to the SM2.0 shaders. If you see these your graphics card may be too old for KSP.

Windows Specific Issues

In addition to the below, the Cross-Platform Bugs and Possible Fixes thread currently contains a few Windows specific issues.

32-bit operating system with a multicore processor

The game engine that KSP runs on (Unity) has an issue with memory allocation using a 32bit OS on a multicore CPU. This issue causes at least 50% of all crashes on Windows so it's definitely worth checking. Click this link to see how you check if you're running on a 32 or 64 bit operating system, to check if you have a multicore processor open Device Manager and look under processors: if more than one is listed you have a multi-core processor. KSP Will most likely not run properly if you find that you have a 32 bit operating system and a multi-core processor. If you run KSP on such a configuration it will try to allocate RAM that is either in use or does not exist causing frequent random crashes, this can be solved in three different ways:

  • Upgrade to a 64-bit Operating System. This is the easiest and in the end probably best solution and recommended for users who are not comfortable changing vital system files. Windows license keys are valid for 64bit and 32bit versions of Windows, but you will need to source 64bit installation media.
  • Set the process affinity to make KSP use only one CPU core. Click this link for more information.
  • Enable extended RAM support in Windows. Click this link for more information.

Windows Data Execution Prevention (DEP)

Another big cause of crashes is Data Execution Prevention interfering with KSP. Symptoms include the game not saving settings and/or not writing anything to it's output_log.txt file located in the \KSP_Data\ folder. The issue is caused because KSP is not an installed program, but can fortunately be remedied fairly easily and fixing it should thus always be attempted before posting a support request.

  • Copy (not move) your KSP installation away from the C:\Program Files\, C:\Windows and C:\Users folders, this includes places such as My Documents and your desktop. Copy the KSP folder, then paste it to C:\ or a folder you create there directly, such as C:\KSP or C:\Games. You can then create a shortcut by rightclicking KSP.exe and placing that shortcut on your desktop for easy access.

Note that this may make you lose your savegames. You can take a look in this thread to see where they are located so you can recover them.

Folder permissions

You'll want to make sure that the KSP folder can be written to: rightclick the KSP folder (by default KSP_win) and click properties. Uncheck the 'read only' checkbox and hit apply. A small window may pop up asking you to apply these settings to just the folder or all subfolders and -files. Check the latter and press ok.

Starting KSP takes several minutes or more

This is caused by a bug in the game engine (Unity) that we cannot fix at this time. However, there is a workaround available that involves removing all unused/inactive (virtual) network interfaces such as Hamachi.

Incompatible software

Some programs will cause KSP to crash, so far these are:

  • Gigabyte OC guru
  • Avast! 8 Anti Virus suite
  • Fraps if started before KSP
  • IDvault
  • WMWare

Mac OSX Specific Issues

In addition to the below, please see here for Mac Specific Bugs and Possible Fixes.


Most OSX issues are permissions related, solve these by enabling read/write permissions on the KSP_osx folder. To do this, open a Terminal, change the directory to where the KSP_osx is and type: "sudo chmod -R 777 KSP_osx" (without the quotes). For more information on OSX permissions and how to do this graphically, please see here.

Saved state issues

OSX saves the state of programs it runs. Sometimes these files are corrupted and need to be deleted for a program to run properly again. Click this link to learn how to find the saved states; the one you need to delete is the unity.Squad.Kerbal Space Program.savedState folder.

Linux Specific Issues

In addition to the below, please see here for Linux Specific Bugs and Possible Fixes. Also, Kerbal101 has written a launcher script that allows to set most of the options conveniently.

No text shows up in the settings menu

To fix this issue you need to install the arial.ttf and arialb.ttf fonts to your installation, this can be found in the ms-corefonts.ttf or eufonts packages.

The VAB is weird and everything is the wrong size, maneuver nodes are jittery, significant lag/stutter, or part attachment nodes out of alignment.

This is due to some languages using commas as periods, start KSP with "LC_ALL=C ./KSP.x86" or "LC_ALL=C ./KSP.x86_64"

After making this change, you will likely have to delete your settings.cfg file as well as any saves that were created or loaded while running KSP without the LC_ALL=C command.

Edited by Deddly
Fixed some of the links
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