# Mach 4 crashes after loading toolpath **URL:** \ **Category:** General Chat\ **Tags:** mach4\ **Created:** [May 18, 2026, 1:18pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153 "2026-05-18T13:18:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![pviljoen2](https://avatars.discourse-cdn.com/v4/letter/p/85e7bf/32.png) [@pviljoen2](https://forum.avidcnc.com/u/pviljoen2)\ **Post date:** [May 18, 2026, 1:18pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/1 "2026-05-18T13:18:56Z")
It finally happened, controller system committed suicide, keyboard failed, weird movement when pressing keyes etc. I build a new system, actually 4, 2 on win8.1 and 2 on win10. Each gave me exactly the same problem. The whole program crashes as soon as you load any toolpath. eventually usend the demo path code from the install, same problem, so it is not my toolpath code. Using the latest avidcnc code and doing a clean install everytime. Tried both win10 (22h2) and Tiny10, all with the same problem. I can load the GUI code and it is stable. If select the second tab (Offsets) and then load the demo toolpath (roadrunner) the code loads fine. AS soon as you switch to the run program tab, the system starts crashing. Everything closes down, even the trace window. Nothing is remember in history or the trace/debug wizard. This is the alternative to loading the code directly in the run tab, where everything crashes immediatly I did read somewhere that it maybe a graphic card issue, checked and upgraded, still the same problem. card has 3 or more gb ram. 4 systems. ---
**Author:** ![PaulC](https://avatars.discourse-cdn.com/v4/letter/p/e9a140/32.png) [@PaulC](https://forum.avidcnc.com/u/PaulC)\ **Post date:** [May 18, 2026, 1:34pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/2 "2026-05-18T13:34:42Z")
It sounds like you can load g code, you just can’t display the path. You could test this by disabling the display of the toolpath (I did this on my mach 3 machine). If disabling the toolpath works, and the toolpath is simple, it is pointing to graphics issues. You might try changing the display resolution to see if that changes anything. Make sure that you have not run out of disk space. Check permissions on where ever mach 4 writes temporary files. ---
**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\ **Post date:** [May 18, 2026, 2:45pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/3 "2026-05-18T14:45:02Z")
Did you copy Mach 4 from your old system or install it fresh? ---
**Author:** ![pviljoen2](https://avatars.discourse-cdn.com/v4/letter/p/85e7bf/32.png) [@pviljoen2](https://forum.avidcnc.com/u/pviljoen2)\ **Post date:** [May 18, 2026, 3:07pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/4 "2026-05-18T15:07:30Z")
Installed fresh everytime. The problem has been isolated to the run screen layout. Made sure to have enough diskspace - 250gb and enough screen ram. Very small path g-code, demo roadrunner code. ---
**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\ **Post date:** [May 18, 2026, 4:29pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/5 "2026-05-18T16:29:47Z")
I don’t have Mach up right now, but there are some settings in an advanced tab somewhere that have something to do with how that G code window renders… If memory serves it’s in the setup window with all the tabs and it’s near the end of the tab list ---
**Author:** ![pviljoen2](https://avatars.discourse-cdn.com/v4/letter/p/85e7bf/32.png) [@pviljoen2](https://forum.avidcnc.com/u/pviljoen2)\ **Post date:** [May 19, 2026, 9:34am UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/6 "2026-05-19T09:34:59Z")
Under Operate → gui settings updated the suppress toolpath Regen Threshold to 1000. It was set at 0. Changes back to program run tab. Loaded the roadrunner demo code, and it has not crashed. ![20260519_113340](https://canada1.discourse-cdn.com/flex027/uploads/avidcnc/original/2X/f/f7e5cd7acb614aa1dc8a78fbb1b651375bbd9ca4.jpeg) ---
**Author:** ![pviljoen2](https://avatars.discourse-cdn.com/v4/letter/p/85e7bf/32.png) [@pviljoen2](https://forum.avidcnc.com/u/pviljoen2)\ **Post date:** [May 19, 2026, 1:52pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/7 "2026-05-19T13:52:04Z")
UPDATE: looks like the number 1 in this field works the best for mach4 demo code and for my toolpaths. Now have a license problem, that loads fine but system does not come out of demo mode. BTW, if you change this field, make sure to shut and restart the system. It does not save the value either wise. ---
**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\ **Post date:** [May 19, 2026, 3:08pm UTC](https://forum.avidcnc.com/t/mach-4-crashes-after-loading-toolpath/6153/8 "2026-05-19T15:08:22Z")
If you’re on a new PC you’ll likely have to generate a new license from Mach 4. You’ll need to login there to get it. > **[Mach4 Software Licensing - CNC Software](https://www.avidcnc.com/support/instructions/software/mach4Licensing/)**