Opera installer 71.0.3770.228.0

Fatal error upon loading installer executable:

In line 199:The system cannot find the file specified., In line 273:The operation completed successfully., In line 304:The operation completed successfully., In line 199:The system cannot find the file specified., In line 273:The operation completed successfully., In line 308:The operation completed successfully., In line 178:The specified procedure could not be found.,

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OK

Close Opera.

Open up the Windows task manager and end task on any Opera processes that are running.

Delete Opera's install folder. By default, that's "C:\Users\yourusername\AppData\Local\Programs\Opera" or "C:\Program Files\Opera" depending on whether you did a current-user install or an all-users install. Or, in your case, wherever you installed Opera.

Delete all Opera-related files and folders in "C:\Windows\temp" and "C:\Users\yourusername\AppData\Local\temp". (This is probably the only part (besides closing all Opera tasks in the task manager) you need to do if you want to try it first.)

Open up the Windows task scheduler, click on "Task Scheduler Library" and delete all Opera tasks in the right-hand pane.

Open up regedit and delete any Opera uninstall keys in "HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" or "HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall" depending on whether you had Opera installed for the current user or all users.

Also in the registry, delete any Opera-related strings in "HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run", "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" and "HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Run".

Also in the registry, delete any Opera-related keys in "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet" and "HKEY_CURRENT_USER\SOFTWARE\Clients\StartMenuInternet".

Also in the registry, delete the "HKEY_CURRENT_USER\SOFTWARE\Classes\OperaStable", "HKEY_CLASSES_ROOT\OperaStable", and "HKEY_LOCAL_MACHINE\SOFTWARE\Classes\OperaStable" keys.

Also in the registry, delete any Opera strings in "HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications" and "HKEY_CURRENT_USER\SOFTWARE\RegisteredApplications".

Also in the registry, delete the key "HKEY_CURRENT_USER\SOFTWARE\Opera Software".

Delete and unpin any Opera shortcuts you have. Restart Windows after that or restart Windows Explorer in the task manager on the processes tab.

Then you'll be good to go to reinstall Opera.

Download https://ftp.opera.com/ftp/pub/opera/desktop/71.0.3770.228/win/Opera_71.0.3770.228_Setup_x64.exe, launch it, click "options" to make sure all the settings are how you want, and install.