Is there any way to contact Opera and get this back??

... What do you think about using cloud storage? How reliable is it to upload personal files there?

A lot of people use (or even rely on) cloud storage for backups; others prefer their own physical backup media. Much depends on the nature of your data, your technical proficiency, and your levels of trust.

It must be understood that the "cloud" is actually a storage drive in a physical server-computer owned by someone somewhere and accessed over the Internet. Backing up to the cloud always involves trusting a 3rd party with your data - either a backup service, a cloud-space provider, or the middlemen involved in the forwarding chain of moving the data into the cloud and recovering it back again. The trust you must extend depends greatly on the nature of your data: is it extremely sensitive (at a personal, commercial, or national level) and how vital to you is it - really?

For many ordinary users, a reputable cloud backup provider is an acceptable backup alternative, provided that the user has reasonably stable Internet access available all the time. Depending on the nature of the data, file encryption/decryption may need to be employed to better protect privacy while moving data to/from or while stored in the cloud.

For users who simply want to keep control of their data or whose data is very sensitive or mission-critical, data files should be backed up physically on a local basis, verified, and media kept safely stored - preferably with a copy in an off-site location (in case of fire/storm damage or theft). Physical storage can range from a USB thumb-drive to a full external hard-drive, depending on the amount of data being backed up.

In the case of browser data like in Opera, there is another possibility for ordinary users. Normally, important browser data consists of customized settings, history, tabs, passwords, sessions, etc. One can simply back up just the browser's user data folders to a separate location on the local drive or an external thumb drive. That provides the ability to easily restore that data should the browser or its regular data folders get hopelessly messed up.

Regardless, a key observation is that backups should be re-made as often as required to keep the backed data from becoming too stale or out-of-date. This is where many users fail... eg, they need data from within the past week, but their most recent backup data is 3 months old.