By mistake, installed an extension, SketchUp version won't support it

I wanted to animate my robot models. These models are fairly complex, so I felt I should look through the animation extensions and see if there was one that seemed oriented toward complexity. You can see some of my models at my 3D collection named pistonrobot. I thought Simfonia looked like an extension that would work, so I added the trial version. Unfortunately, I just didn’t catch that SketchUP would “load” an extension even if this extension does not have a version of itself for the version of SketchUP involved. I use SketchUP Pro 2015. So now, every time I load SketchUP, it pops up an error message along the lines that SketchUP can’t find one of the Simfonia “components or folders, or executables, or something like that.” I tried uninstalling and re-installing SketchUP, but it did not help. Any ideas ?

How’d you load it? If you loaded it via the Extension Warehouse, go there (Window->Extension Warehouse), sign in, go to My Extensions, find Simfonia, uninstall. You’ll get a message “The extension has been successfully uninstalled, but cannot be dynamically unloaded. The next time you start SketchUp, it will not be loaded.” So restart SketchUp and see if it’s OK.

If you did it by hand, you’ll have to uninstall by hand. Mac or PC locations are different, which are you?

The best way to get specific help, for this specific error, is to copy the error message, then come back and edit your original post, and paste the error message text between lines of 3 backticks, ie
paste error text here

If the text is not triple quoted this way,… the forum swallows some of the most important parts of the message.
(You can also use phpBB [code] [/code] tags to surround the error text, if you prefer.)

BTW, it is SketchUp like in the site header, not SketchUP. (It’s a registered trademark and brand name.)

Here’s help with installing/uninstalling extensions.
Notice it includes the file path if you need to manually uninstall.
Installing Ruby Plugins (Extensions) — SketchUp Help

Additional background documentation…
SketchUp Plugin Compatibility — SketchUp Help