Hmmm that's odd. Anyone else with this problem?

The problem is in two different computers where I log into my Steam account and where I play TT2+. The computers have got Windows 10 x64 system.

The newest problem: In two user levels ("Up there are so many creatures" by arachnetz and "Part nine Buttercups Great Adventures" by Murf Rock) the game crashes. In the first level the problem is after collecting all collectibles (includes Wings), before the exit. In the second level the game crashes a few seconds after entering the level.
The crash is:

"Fatal Error
An unknown error occured, causing the application to shut down. If the problem persists, please support the developer at http://www.twotribes.com/support

This is only correcting the text of the crash, not change.

Hmmm.. this is not soo good. Do you know if this happens to everyone?

I checked another account in one of the computers with installed games from my profile. In that account (gridenator), is the game TT2+ and TT2+ level editor, too. The same problem.
I reinstalled the game and the level editor. It didn't solve the problem.

The problem is in this account (found in the post no. 4).

Edit: I played thd whole official scenario again. There is no code of the graphics of the Telepathic Ancient Frogs. But there are some text messages from them. This is controlled by an entity like Telepathic Ancient Frog Message Triggers.
NEW:
I found that the Steam alert (Error 86) is displaying because the files matched with the entity (Telepathic Ancient Frog Message Trigger) or editor files are probably incomplete. It probably causes the problem (Error 86) when trying to open the level editor. Or maybe useless file (workshop_temp_preview_image)?

To solve this, I'd like to check the update fix or degrade TT2+ version to that before the Major TT2+ Update. But is there a way to degrade the game's version?

NEWS:
I asked Tony7003 in his level's (called "level 3") Workshop page about the problem. He answered that he isn't able to open his level editor, too (Staam alert: error code 86), so it seems the problem is happening to everyone with Windows 10 64-bit who has got TT2+ and TT2+ Level Editor in Steam.

Notice: He confirmed the problem in the post below.

hello I have the same problem. impossible to launch the editor for the update ca said failure of the launch Toki tori2 + error code 86. I play on pc Windous 10 64 bit

I accept the Tony7003's failure text. My text wasn't original English, it was translated.

Same issue in Win 10 64 bit here. Have you found a solution?

This is happening to me too. Win 10, 64bit.

Same here. Steam always downloads the editor almost instantly, which makes me believe it's not actually downloading any data at all. I can't find a corresponding executable anywhere either. I'm using Windows 7 64-Bit.

Edit: Just figured out it did in fact download a single file: workshop_temp_preview_image.png
So I'm almost certainly missing data.

Edit #2: Same with my Windows 10 64-Bit PC. At this point, it really looks like you forgot to include most of the level editor's files with the latest version.

NEWS: killcool 64 said there is only one file downloaded. Error code 86 says that there's much data empty so it can't open the level editor. That's true.
Now a player must inform the game dev that the reason of the error is found - dev has forgotten about including the level editor's all files except 'workshop temp preview image' to TT2+'s asset.
You can report it by sending an email to support@twotribes.com

Two Tribes is now going to fix TT 2+ Level editor!
- Expected hotfix: February
Workaround for now:

引用自 nielsthooft：

Go to the games Steam Properties > Launch Options, and enter "--editor" there.

However, this is not a full solution, you'll have to revert it to the previous state to make Toki Tori 2+ Standard Game working again.