Also, look for the people who actually create the plugins. Some malicious plugin creators copy the code of legit creators’ plugins and insert viruses, then publish it and bot it to the front page under the same name.
I’d watch out for that tree one, be careful with that. I’d suggest deleting all the trees in the game and disabling the plugin, then seeing if the problem still occurs.
How should I remove the plugin?
Like I said, go into manage plugins and disable all of your plugins, and then see if it still happens.
Try going into the physical plugin folder in the Studio file system on your device. I’m not sure the path, you should google it. Look for plugins in there if you can. If you can find the tree plugin in your Manage Plugins, that’d be even better.
I can’t. It’s not in manage plugins.
Hmm, try the file path option then. Maybe google the directory to Roblox Studio in your device’s hard drive, then try to find a plugin folder and remove the tree plugin from there.
Try to uninstall it via your roblox inventory.
^ Or that, try that if my solution doesn’t work. I wish you luck finding the cause. 
Have you already used the virus detector plugin?
Yeah. I installed and ran it. It removed 101 parts.
If I full uninstall and install studio?
Don’t think it will do much, the plugins automatically reinstall from your inventory. Try going into your inventory and deleting it from there on the ROBLOX website.
I don’t think the tree generator plugin has the virus.
But there are many plugins in your inventory that you may not be using and some are even moderated, you may be able to remove them.
Sorry for answering your comment Gyghioa , it was a mistake.
Agreed, Defaultio is a trusted developer and would not add viruses.
He literally made Lumber Tycoon 2, a very popular game. Definitely trusted.
You can use the “find tool” and then type purchaseprompt to see if a script has it. So whether it’s because of scripts in your game or the plugins.
Do Ctrl + Shift + F and look for require(, it checks all scripts at once. If you can’t find anything suspicious, go to the explorer search bar and look for ‘Script’. Otherwise, if all else fails, delete all of the free models, I guess.
He’s already done that I think, but the code may be obfuscated. I had the same problem in my old game I shutdown; it would teleport the users randomly to a place to get visits then teleport them back.
He’s deleted all free models in his game, and all his plugins are trusted. I’m lost at what to do, the only thing I think could be a problem is obfuscated and malicious scripts. (He has done Find tool to find PromptPurchase)
These two scripts come when I reset the studio. I delete them for uncountable times.