After installing OS X El Capitan Itunes display error message: This copy of iTunes is corrupted or not installed properly. Reinstall iTunes. (-42,037),

Apple Support has given the following instructions to others who had a similar problem.

First, back up all data.

Select the iTunes icon in the Applications folder and open the Info window. Click the padlock icon in the lower right corner to unlock the settings.

In the Sharing & Permissions section, change the Privilege setting for each Name in the list to Read & Write. Close the window. If the settings aren't visible, click the disclosure triangle on the left so that it points down.

You should now be able to drag the iTunes application to the Trash and empty. Your iTunes data won't be affected.

Then download the iTunes installer package and run it.

It worked for me too. Thank you for taking the time and share. Good day.

also helped me when iTunes just gave message about low volume then the 42037 message. Much easier than reinstalling whole OS system.

Thanks