How to Save Sessions in an Opera Browserby Nick Peers
Opera 25 for Windows no longer has the Sessions feature, so you can no longer use it to save entire sessions. You can, however, save all open tabs as a Speed Dial folder and open them all at once later from the Speed Dial page. Furthermore, you can add new pages to the folder if you want. You can rename the folder and configure Opera to display the Speed Dial page when you launch it.
Creating Speed Dial Folders
Open all the tabs you want to save, right-click one of the tabs and choose "Save tabs as Speed Dial folder" to save the entire session. Opera doesn't assign a name to the new folder automatically, so you need to do it manually. Click "Opera," click "Speed Dial" to open the Speed Dial page, right-click the folder and click "Edit title." Type a name and click "OK." To open all the Web pages in the folder at once, right-click the folder and choose "Open all" from the context menu. To add new pages to the folder, click the folder, then the "+" button, type each address and click "Add it." To display the Speed Dial page when you launch the Web browser, click "Opera," "Settings" and then the "Open the start page" radio button in the On Startup section.