If this issue is only happening with Melodyne, you will want to log into your Celemony account and verify that you have downloaded and installed the latest version. If you have, you may want to try uninstalling and re-installing Melodyne. Make sure that you run Melodyne in standalone mode and activate it, prior to loading it into Studio One.
On the Studio One side of things, for general troubleshooting, you will want to try uninstalling/re-installing the program and then remove your settings files. Here are instructions for removing the settings files:
Go to Help>Open Settings folder.
Copy the contents of the folder over to a folder on your desktop.
Close S1 and delete the contents of the settings folder with the exception of the user.license file as well as the "Extensions" folder.
Open S1 and go to Studio One>Options (Preferences on a Mac) to reconfigure your settings.
Test to see if the problem is resolved. If it is not, please feel free to copy your settings files back over from the backup that you created in step 2.
*If you are missing presets or Sound Sets after doing this, simply double-click one of your Sound Sets under Documents>Studio One>Sound Sets.
As there is not enough information in this question to give you a specific answer, you may want to log into your my.presonus.com account and click on the "Support" tab to create a ticket. The PreSonus team would be happy to assist.