New
#11
DeVandal, again, thank you for your help. I followed Microsoft's instructions to the letter in RegEdit:
Then I rebooted. I still didn't have a MAILTO protocol. I tried a MAILTO link in Internet Explorer and same result: "Could not perform this operation because the default mail client is no properly installed."
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Noticed that I inadvertently set the default value for HKEY_CLASSES_ROOT to URL:MAILTO Protocol. I doubt that hurt anything, but I deleted it. Now I'll reboot and try again.