Oh no! You’re WordPress site went down!
Are you getting a fatal error with a path that has JetPack in it? When you try to go to log into the admin portion of your site you’ll probably also see something like this:
Fatal error: Cannot find a library with slug admin-pages/class.jetpack-landing-page. in ...
Don’t freak out just yet. I had this same issue and for me the fix was very simple.
First Step: FTP
Find your FTP credentials for your site. This shouldn’t be too difficult. If you did the install for WordPress not using an automated tool from your hosting provider then this and the next step should be pretty easy. The fix will involve using FTP to fix the JetPack plugin directory.
You’ll also need an application to FTP into your site. I recommend WinSCP. It supports SCP, FTP, and SFTP. It’s also free and easy to use! Download, install WinSCP, and open WinSCP, or open up your favorite FTP application. You’ll then want to log into the FTP server.
Download the Latest Version of JetPack
We’re going to be manually update the JetPack. This means you’ll need to head over to the WordPress JetPack site and download the zip file. After extracting the zip you should have a directory named jetpack.
Navigate To Your Plugins Directory
The problem lies within a botched upgrade of the JetPack plugin. On your FTP site you’ll want to go to the wp-content folder and then the plugins folder. Inside the plugins folder you’ll see a folder for each plugin installed on your site.
Backup the JetPack Directory
Before we modify anything it’s always good idea to backup what we’re going to be touching. With your FTP application download the jetpack folder to you local storage. Make sure when you’re downloading, and this is especially true when you’re using the dual pane type FTP application like WinSCP, that you’re not downloading into the same folder that you’ve extracted the jetpack folder which was downloaded.
Delete the Remote JetPack Directory
Now that you’ve backed up the jetpack directory from your server to your computer you can safely remove the directory in the plugins folder.
Upload the Extracted JetPack Directory
Now that you have no folder called jetpack in your plugins folder you can upload the directory that was created from the extracted zip. When I did this process the upload took a bit of time. The total size was in the neighborhood of 30MB.
Refresh Your Site
After the upload completes you should be good to go! Go to your site and refresh. If you still get an error try cleaning the cache on your browser. If things still appear to be broken you can go back to the FTP application and navigate back to the plugins folder. Delete the jetpack folder. Try refreshing your site again. If this works you may want to try logging in as an administrator and have WordPress do the install through the UI.
Hopefully this clears up your problem!