library error Servo.h

I'm teaching a High School STEM class using Arduinos. One of the students is getting an error when uploading relating to the library. (I wish I would have written down the exact error but I didn't) The only library we are using now is Servo.h
Can someone tell me how to re-load that library. I never specifically loaded it and I don't really understand where these libraries are so any help on that would be appreciated also.

The library is included as part of the IDE.
Should only need
#include <Servo.h>
at the top of the sketch.

What did they have selected in the Tools > Board menu?

The Servo library is included with the Arduino IDE at {Arduino IDE installation folder}/libraries/Servo.

Some hardware packages include modified versions of the library.

If you use an older version of the Arduino IDE you can update the Servo library to the current version via Library Manager, which installs it to {Sketchbook folder}/libraries/Servo. Depending on settings you may get an updatable library notification prompting you to do this.

The easiest way to determine the location of the library that is in use is to do this:
File > Examples > Servo > pick any example
Sketch > Show sketch folder - this will open the example sketch folder, which is in the examples subfolder of the Servo library.

So it's hard to give exact instructions for re-loading the library without more information. Most likely you could do this by reinstalling the Arduino IDE. There is a very good chance that the solution to the problem has nothing to do with reloading the library.

Thank you - thank you. I'll check to see which board he has selected. It's working for the other students. If he has the right board selected, I'll re-install the IDE. Do you think I'll need to uninstall it from windows?

Do you think I'll need to uninstall it from windows?

Not in the traditional sense like using add/remove programs or anything. When you install Arduino all it really does is copy the files into a folder on your computer. Nothing actually gets "installed" in the Windows sense. So you can just delete that folder where it is installed and start over. You can actually even install several versions of the IDE on one computer and which one runs just depends on which folder you pick the executable from. All you're really doing is running a java program.

It would really really really help if you could tell us what the actual error was and what code caused it. You might not have any library issue at all. Some of the error messages are a little cryptic if you don't know how to read them.

I'll get that message on Wednesday. Thanks again.

Actually it depends on which download you use. There is a “Windows Installer” download which does write to the Windows registry so if you want to uninstall and reinstall you can’t just delete the installation folder. There is also a “Windows ZIP file for non admin install” download which you just unzip, there’s no installation so no need to uninstall.

Today I wrote down the error:
Invalid library found in C:\Users\Zion\Documents\Arduino\libraries\Sketch_Project_9
(this is followed with 2 more lines naming 2 more sketches)

However, today his program is loading to the Arduino and the servo is working. I thought it was stopping the upload on Monday but maybe not.

Anyway, now it just looks like he has that libraries directory with sketches in it and the IDE is just giving us a warning. It's hard to spend enough time with each student to really resolve this type of issue. Since it's working and we're near the end of the semester, I'll just leave it as is.

Thank you for your replies. Now I understand better how IDE works. I'm saving notes of your help.