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Undo does not work in Blueprint Editor

When I open my vehicle blueprint and change, for instance, the Vehicle Setup>Mass property, then compile, then press undo (regardless of whether Ctrl+Z or through the menu), the Undo information box in the lower right corner shows correctly "Undo: Edit mass", however, the value of the Mass property does not revert to what it was before.

I've seen many other cases when the Undo does not work properly. This is just one example.

Using: UE 4.5, My own project, using vehicle blueprint from sample UE blueprints; Windows 7

Product Version: Not Selected
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asked Oct 16 '14 at 09:48 AM in Bug Reports

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avatar image Keval Shreyas Aug 07 '16 at 11:14 AM

I too had the same problem, this occurs only in 4.12,for me at least, so I restart the editor and it works like a charm again.But it does occur quite frequently.A weird bug :/

avatar image DanzigLucifuge Apr 13 '17 at 02:42 AM

idk I just remember being able to click undo over and over in BP and now seems like I can't undo any changes I make in BP at all.

avatar image Steve Hardister ♦♦ STAFF Apr 13 '17 at 06:45 PM

There are a couple of live bugs that may be causing it to seem that way:

  • UE-43866 Actions in the Blueprint Enum editor are not added to the Undo History

  • UE-31749 Undoing alteration of a local variable's default value does not actually undo the alteration

These are scheduled to be fixed in a later version of the Engine. Additionally, there are a couple of conditions which will make it impossible to undo:

  • After you compile your Blueprint

  • When you Play in the Editor (effectively causing the Blueprint to be compiled.)

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Hi dimitrov,

After compiling scripts, compiling in general, or building your map, the undo option is no longer available. Aside from these conditions, if you can provide other specific examples where Ctrl+Z/Undo is not functioning as expected I will look into it and generate a bug report if applicable.

Thank you for your input!

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answered Oct 16 '14 at 06:15 PM

avatar image CrimsonHawk Jul 25 '16 at 01:07 AM

Can't undo creating a Collision Mesh for example.

avatar image Steve Hardister ♦♦ STAFF Jul 25 '16 at 02:39 PM

I am unable to reproduce this issue with the following steps in UE4.12.5:

  1. Open any project in UE4.12.5

  2. Create a new Actor Class Blue Print

  3. Add Component: Sphere Collision

  4. Enlarge Sphere Collision by a random amount

  5. Ctrl Z - Undo "Enlarge"

  6. Redo "Enlarge"

  7. Compile and Save Blueprint

  8. Ctrl + Z to Undo "Enlarge"

  9. Redo "Enlarge" RESULT: Works as expected.

Please try these steps in UE4.12.5 and let me know if you are still getting this bug. Otherwise, list the steps in this manner in order for me to reproduce the bug on our end.


Steve H.

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