Nevermind the above. Just download make_m2_default_client.zip, extract it, view the readme and merge. That should do the trick. (Basically researched how Thunderbird does it and copied it.)

That reg file above worked for me.

I'll update the original zip file still though to also include the %ProgramFiles% reg file (after I make one that uses %ProgramFiles(x86)% too).

Actually, I won't be doing that. Using expanded strings and environment variables didn't work out completely because it breaks MAPI. The MAPI stuff ignores expanded strings for DLLPath and operamail.exe paths. So, one just has to edit the paths in the registry file if they're not where your operamail.exe is at.

I am so sorry. I just found out that Opera Mail was not in Program Files, it was in AppData

Ah O.K. Don't worry about it. You are correct that the Opera Mail installer suggests the wrong path by default. You have to click "options" to not only notice that it's wrong but to fix it.

This could be why the reg fixes don't work right for some. They assume Opera Mail is installed in the right place when it really isn't.

Glad you got it.

I'll update the original zip file still though to also include the %ProgramFiles% reg file (after I make one that uses %ProgramFiles(x86)% too). Then, I clarify about the install directory in the readme.txt.

Nevermind the above. Just download make_m2_default_client.zip, extract it, view the readme and merge. That should do the trick. (Basically researched how Thunderbird does it and copied it.)

I used that one.

I think it is just about the configuration of the folders which need to be changed in reg file.

Try this reg file. It uses the %ProgramFiles% environment variable for all the paths. In other words, it uses "%ProgramFiles%\Opera Mail\operamail.exe" instead of "C:\Program Files\Opera Mail\operamail.exe" so that it works on any locale and even if your drive isn't C:/. This one is specifically for 32-bit versions of windows like you have.

I tested that all the keys looked right after importing. However, I have 64-bit windows, so I wasn't able to test if "Opera M2" shows up in "Default Programs" and whether MAPI works (right-click on file on desktop -> send to -> mail recipient").

I think it is just about the configuration of the folders which need to be changed in reg file.

That's what it looks like as in the pic you posted, it just listed a path like it wasn't able to find what it was looking for.

My system is 32bit

Oops, sorry. I probably have missed it.

//%Program Files%// or %Program Files%

You'd replace C:\\Program files\\Opera Mail\\operamail.exe with %ProgramFiles%\\Opera Mail\\operamail.exe. But, it needs to be an expandable

string like mention in my comment above. That shows how to do it. It's a little tedious though.

I can create a new reg file for you that uses %ProgramFiles%. But, I probably won't be able to do it until tonight/tomorrow.

When I open Opera Mail folder and click address bar it changes from Arquivos de Programas to Program Files

In Windows Explorer, in C:, what's the name of the program files folder? Even if the address bar changes it to Program Files for you, I don't

know if windows will automatically redirect Program Fiels to Arquivos de Programas for commands in the registry. This means that it might have to

be Arquivos de Programas in the commands. Then again, you said that didn't work. If I make a reg file that uses %ProgramFiles%, you shouldn't

have to worry.

Then again though, the simple reg file I original posted with just the Opera.Protocol tweak didn't work for you. This might mean there's

something extra that needs to be done for your setup for some reason.

What about "Arquivos de Programas (x86)" or "‪C:\Program Files (x86)"?

Previous comment said he was using 32-bit 8.1, so that shouldn't be the case. But, won't hurt to check.

I tried to put Arquivos de Programas in the path but still not working.

What about "Arquivos de Programas (x86)" or "‪C:\Program Files (x86)"?

I tried to put Arquivos de Programas in the path

Is that the name of your program files folder or no?

When you replace all the paths in the 32-bit reg file, are you replacing just "Program Files" with "Arquivos de Programas" or are you trying to replace the whole path with your new path? If the latter, you need to make sure things are escaped properly.

No, it doesn't

Is the program files folder in your locale really named "Program Files"? If not, you'll need to make sure all the paths use the name you see in windows explorer.
For example, if it's "Arquivos de Programas", the paths need to be that. Or, you need to make all the strings that have paths be expanded strings in the reg file and use %ProgramFiles% in their values.

I tried to put Arquivos de Programas in the path but still not working.

No, it doesn't

Is the program files folder in your locale really named "Program Files"? If not, you'll need to make sure all the paths use the name you see in windows explorer.

For example, if it's "Arquivos de Programas", the paths need to be that. Or, you need to make all the strings that have paths be expanded strings in the reg file and use %ProgramFiles% in their values.

The best way to create an expanded string is to create a new key in the registry, right-click in its pane to create an expanded string. Then, enter the command "%ProgramFiles%\Opera Mail\operamail.exe" "%1" for its value and then export the key. Then, you can view the exported reg file in a text editor so you can copy it over to my example reg file.

For example, in a reg file, the expandable string Test with its value set to "%ProgramFiles%\Opera Mail\operamail.exe" "%1" would look like this:

"Test"=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00,61,00,6d,00,46,00,69,\
  00,6c,00,65,00,73,00,25,00,5c,00,4f,00,70,00,65,00,72,00,61,00,20,00,4d,00,\
  61,00,69,00,6c,00,5c,00,6f,00,70,00,65,00,72,00,61,00,6d,00,61,00,69,00,6c,\
  00,2e,00,65,00,78,00,65,00,22,00,20,00,22,00,25,00,31,00,22,00,00,00

look this:

Does clicking the first one work then?

No, it doesn't

look this:

Does clicking the first one work then?

Then, make sure HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\OperaMail\Capabilities\UrlAssociations has the mailto string with "OperaMail.Protocol" (no quotes) as its value.

In "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\OperaMail\Capabilities", make sure there are ApplicationDescription, ApplicationIcon and ApplicationName strings in there. The icon one should have the path to operamail.dll,0.

Also, maybe add an "Opera Mail" (or "OperaMail" key to HKEY_LOCAL_MACHINE\SOFTWARE. (Look at the others in there for more info). Or, maybe add the "Opera Mail" (or "OperaMail") key under HKEY_LOCAL_MACHINE\SOFTWARE\Opera Software" instead where the "Opera Mail" (or "OperaMail") key has its "(Default)" string's value set to the path to operamail.exe (no quotes around path). Have a string InstallDir where its value is the path to the folder operamail.exe is in (again, no quotes).

I need to strip all Opera Mail stuff from my registry, install Opera Mail and see just exactly what's missing again.

Make sure HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\OperaMail.exe is present too. Again, "(Default)" string's value should be the path to operamail.exe (path quoted) and Path string's value should be the path to the folder operamail.exe is in (path quoted).

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\OperaMail
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\OperaMail
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\OperaMail.protocol
HKEY_CURRENT_USER\Software\Classes\mailto
HKEY_CURRENT_USER\Software\Classes\Opera.Protocol
HKEY_CLASSES_ROOT\mailto
HKEY_CLASSES_ROOT\OperaMail.protocol

Also, make sure OperaMail is set in the (default) string in HKEY_CURRENT_USER\Software\Clients\Mail

Also, make sure HKEY_CLASSES_ROOT\Applications\operamail.exe is present and that it has the shell/open/command sub-keys with the (default) string's value in "command" key being "path to operamail.exe" "%1" (quotes included). Do the same with HKEY_CURRENT_USER\Software\Classes\Applications\operamail.exe

Also, look in "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\MAILTO" to make sure "operamail.exe" is listed in the "OpenWithList" sub-key. In the "OpenWithProgids" sub-key, Make sure the binary "URL:MailTo Protocol" is present (with its value set to nothing (as in, just the 0000) as that's what the default string's value in "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\OperaMail\Protocols\mailto" points to.

Make sure there's a string in "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\OperaMail\Protocols\mailto" that's "URL Protocol" with no value set. Make sure there's a dword named "EditFlags" (no quotes) with its value set to 2.

Also, make sure "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\OperaMail.exe" is present and that its (Default) string's value is set to the path to operamail.exe (in quotes). There should also be a "Path" string where its value should be the path to the folder operamail.exe is in (with the trailing backslash and the path in quotes). There are no sub-keys to this OperaMail.exe key.

Also, in HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\OperaMail\Capabilities\UrlAssociations there should be a "mailto" string where its value is set to OperaMail.Protocol. In "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\OperaMail\Capabilities\Startmenu", there should be "Mail" and a "StartMenuInternet" strings strings with both their values set to "OperaMail" (minuse the quotes).

In "HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail\OperaMail", make sure the DLLPath string's value is the path to OperaMAPI.dll (do not quote the path). The (Default) string's value should be "OperaMail" (no quotes) and the "LocalizedString" string's value should be "OperaMail" (no quotes).

Make sure all that's right, restart the computer, go into Default Programs in Windows, choose "set default programs", select "Opera Mail" and then choose "set this program as default". Then, after that you can go back to "choose defaults for this program" to confirm and both mailto and MAPI are set. Then, you can go back to "associate file type and protocol" and confirm that mailto is associated with Opera Mail there too.

That might do the trick as long as you don't check the box in Opera Mail's preferences. If it still doesn't work, test to see if it fails just when Opera Mail is already open or not.

If that doesn't help still, maybe delete all the OperaMail keys in the registry and install Opera Mail again (for all users) and then add the Opera.Protocl reg keys etc.

The best wayt to really fix this is to pretend that operamail.exe is your program and research the microsoft docs for how to properly add it to the registry so that it's associated with mailto, news and MAPI. Then, maybe someone can write a script that you put next to operamail.exe where when you load the script, it adds all the necessary stuff to the registry for that operamail.exe.

AFAIK there's a bug with the opening of mailto: links in Opera's latest versions. Which version were you using primarily when doing these tests @sidneyneto?

The latest Opera Mail standalone version.

I edited the reg file several times and the only I could do it is to put Opera Mail as defaut to open MAILTO protocol, but when I try to open mailto, it does not happen nothing

Hmm, not sure why it works for some (and me), but not others.