How to prevent union loss due to corruption, and how it happens

[RealDipperBot (TamakiAmajiki)]

Any union, no matter how complex or how small is at risk at getting corrupted for no reason upon publishing the game. Here is how to prevent it and what you should NOT do until you are absolutely sure the union is ok.

Step 1. Have two places open, an empty place and the place you’re making the unions in.

Step 2. When you finish your union, copy paste it to the other place. Do this with every union you have made and do NOT publish until every union you have made in that session on roblox studio is on the second place you opened up.

Step 3. Once you’re finished with your unions, publish but do NOT close studio yet. (NOTE: Only publish the place in which you originally made the unions, the second place is a backup in case the unions got corrupted, how to fix the corrupted unions up soon.)

Step 4. Go in-game and look around to see if any of the unions disappeared. Generally, because of the second place for some odd reason they turn out fine and if none of the unions are corrupted you can safely close studio and then publish and close the backup place.

IMPORTANT NOTE: Once you publish and all the unions are safe, do NOT continue working on your game until you close studio completely and then re-open it. For a strange reason if you continue working on your game or move even ONE object, EVERY union which was previously ok will now be corrupted. (Trust me, i know from
experience.). Once you close the place and re-open it, you can safely continue without worry of the previous unions ever getting corrupted. (But if you seperate and re-union it you’re gonna need to repeat the process.)

IF YOUR UNIONS DID GET CORRUPTED:
Step 1. Copy paste the position of the corrupted union into a note pad or anything you can type in.

Step 2. Delete all copies of the corrupted union or this will not work.

Step 3. Copy paste the safe union in the backup place into the other place in which you deleted the corrupted unions and the place you actually need the union in.

Step 4. Publish and then check your place in-game again to see if the union is safe, it generally will be save but sometimes this process will take up to 3 tries.

Step 5. Close the place and then publish and close the backup unions place.

And there you have it, How to fix the very annoying union disappearing bug and why it happens for those of you who have failed to replicate it.
NOTE: The most common unions to get corrupted are any unions with negative parts, most the time unions which don’t have negative parts will be safe, unless of course it’s very complex. Another union that gets corrupted easily is if it has spheres or cylinders.

If you want to recover already-lost unions:

How to recover invisible / corrupt unions

Introduction This tutorial will walk you through finding and recovering your unions if they get lost / corrupted / turn invisible. This method relies on trial-and-error, and works best if tried immediately after you’ve lost a union. Background Information When a union is created but before it or its place is saved, it contains child data - information about what it’s made of, stored directly in the place. When the union is saved to Roblox, a new SolidModel asset is created. The union instance …

[PeZsmistic]

I think it’s worth linking to this tutorial as well, so users who end up here after searching who have already lost unions know where to go.

How to recover invisible / corrupt unions

Introduction This tutorial will walk you through finding and recovering your unions if they get lost / corrupted / turn invisible. This method relies on trial-and-error, and works best if tried immediately after you’ve lost a union. Background Information When a union is created but before it or its place is saved, it contains child data - information about what it’s made of, stored directly in the place. When the union is saved to Roblox, a new SolidModel asset is created. The union instanc…

[RealDipperBot (TamakiAmajiki)]

Agreed, thank you for the suggestion i’ll do it now.

[archcortex]

After loosing all my unions in a new vibe game I created this tutorial has helped me gratefully in making sure my unions are always ‘in tact’.

[Almonty7655 (BusDriverAlmonty)]

I must have been lucky since I have been working with loads of unions on buses I build and other stuff and have never encountered this bug. So I’m gonna take a break from building until I can get confirmation that this will be fixed.