# \[Solved\] Error: Object reference not set to an instance of an object **URL:** \ **Category:** Bug Reports\ **Created:** [January 22, 2026, 2:27pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214 "2026-01-22T14:27:12Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![CosmoKramer](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/cosmokramer/32/6636_2.png) [@CosmoKramer](https://prepomax.discourse.group/u/CosmoKramer)\ **Post date:** [January 22, 2026, 2:27pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/1 "2026-01-22T14:27:12Z")
I’m running into this error when trying to assign loads. I’ve tried reopening the file but then I get another error: “The parameters could not be evaluated. Check the parameter equations” and no 3D displayed. I’ve looked at this [topic](https://prepomax.discourse.group/t/error-message-object-reference-not-set-to-an-instance-of-an-object/1122) but it didn’t help solve my case. I’ve also tried relocating the file to desktop and still no luck. Hope it’s not corrupted as I’ve spent some time assigning materials and creating sections. Here’s the link to the [file](https://1drv.ms/u/c/eec7215cdc16258e/IQCS6PjoYM68Q7Um8hWafMdpASPVSAy6Oc_aQLRTlGhWJT8?e=k22bFa). ---
**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\ **Post date:** [January 22, 2026, 2:47pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/2 "2026-01-22T14:47:03Z")
> [@CosmoKramer](#): > > I’ve tried reopening the file but then I get another error: “The parameters could not be evaluated. Check the parameter equations” and no 3D displayed. Check this thread too: [Warning: v2.4.3 corrupts model](https://prepomax.discourse.group/t/warning-v2-4-3-corrupts-model/3165) Again, you should make sure you aren’t using directories requiring admin rights and you don’t have McAfee antivirus, for instance. Is it in v2.4.0 ? If you have the command history of the model, you could try regenerating it (there are options for that in the Edit menu). ---
**Author:** ![CosmoKramer](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/cosmokramer/32/6636_2.png) [@CosmoKramer](https://prepomax.discourse.group/u/CosmoKramer)\ **Post date:** [January 22, 2026, 3:06pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/3 "2026-01-22T15:06:38Z")
> [@FEAnalyst](#): > > Is it in v2.4.0 ? Yes. It’s my personal computer so I’m admin. Have put the programme in Documents as that what some people here suggested. Have also added it as an exception in McAfee. Don’t have the command history. Will work off from the Desktop this time. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [January 22, 2026, 5:37pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/4 "2026-01-22T17:37:01Z")
Something was incorrectly saved. Can you describe as well as possible your procedure outside PrePoMax and the versions of PrePoMax you were using? Did you create everything in the same version (there is a bug that I fail to find). To get the model working, you can try running the command history again. If you still have the .step file in the same folder, you can rerun all PrePoMax commands using: Edit → Regenerate History. If the .step file is in another folder, use Edit → Regenerate History Using Other Files and select the file. ---
**Author:** ![CosmoKramer](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/cosmokramer/32/6636_2.png) [@CosmoKramer](https://prepomax.discourse.group/u/CosmoKramer)\ **Post date:** [January 23, 2026, 8:40am UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/5 "2026-01-23T08:40:10Z")
> [@Matej](#): > > Can you describe as well as possible your procedure outside PrePoMax and the versions of PrePoMax you were using? Did you create everything in the same version (there is a bug that I fail to find). I’m using v2.4.0 and I used the same version throughout. I redid everything again, this time with both STEP and PMX files saved in the Desktop, and the error disappeared. So my tip to myself and others would be: Always make sure the path name is as short as possible. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [January 23, 2026, 1:20pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/6 "2026-01-23T13:20:07Z")
I think the same happend as in: [Warning: v2.4.3 corrupts model - #13 by Matej](https://prepomax.discourse.group/t/warning-v2-4-3-corrupts-model/3165/13) Where the implemented solution is described. ---
**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\ **Post date:** [February 2, 2026, 5:32pm UTC](https://prepomax.discourse.group/t/solved-error-object-reference-not-set-to-an-instance-of-an-object/3214/7 "2026-02-02T17:32:07Z")