In search type: Registry and select 'Registry Editor' to open.

Locate

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths
• Right click on 'App Paths' and select 'New' > 'Key'
• Name it: outlook.exe

This will create:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\outlook.exe

Locate:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\thunderbird.exe
• On the right it will have two ab listed names (Default) and 'Path' both of type 'REG_SZ'
• Double click on 'Default' name to open 'Edit String' window.
• Do not edit anything.
• Copy all the 'Value Data' - highlight all text, right click and select 'Copy'
• click on 'Cancel' to close as you do not want to save anything.

Locate

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\outlook.exe
• In 'Name' column it will say Default.
• Double click on 'Default' to open the Edit String window.
• In the 'Value Data' text box, Paste in the copied text - right click and select paste.
• click on 'OK' to save

• Right click on the App Paths\outlook.exe and select 'New' > 'String Value'
• Name it : Path

Locate:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\thunderbird.exe
• Double click on 'Path' name to allow you to 'Edit String'.
• Do not edit anything.
• Copy all the 'Value Data' - highlight text, right click and select 'Copy'
• click on 'Cancel' to close.

Locate

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\outlook.exe
• In 'Name' column it will say Path.
• Double click on 'Path' to open the Edit String.
• Paste in the copied text - right click and select paste.
• click on 'OK' to save

This should result in you having both a 'thunderbird.exe' (already installed) and a 'outlook.exe' (you newly created) in 'App Paths

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\outlook.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\thunderbird.exe

When you select 'outlook.exe' it should look identical to when you select 'thunderbird.exe', so both are the same with the exception of the 'App Paths' name.

Your HP printer will look for App Paths\outlook.exe and find it, but it is tricked into using thunderbird program.

You have been so incredibly helpful but I am still getting the error message and think I have done something wrong. I created an outlook.exe. Right now in my regedit all four entries for default and path are the same. They read: C\ProgramFiles\MozillaThunderbird\thunderbird.exe.

I notice above you say that both are the same except for the App Path's name. What should the path say for Outlook?

Sorry...there is a colon after the C

I tried the paths with the (x86) and without and neither worked.

I am about to give up, here. Right now both my outlook and thunderbird defaults and paths in the registry read the same registry:

C:\ProgramFiles\MozillaThunderbird\thunderbird.exe

I have tried to scan and email with this string...no luck.

Then I added the (x86) because my windows is 64 bit (remember I don't actually have an Outlook program on my computer...just the entry in the registry.

C:\ProgramFiles(x86)\MozillaThunderbird\thunderbird.exe

I tried to scan with this string and get the same error message.

re :Then I added the (x86) because my windows is 64 bit

As your computer is 64bit it will put all other windows64bit programs in the 'Program Files' folder. If you download windows32bit programs then they will get put in the 'Program Files (x86)' folder.

But you have already said: Both my Windows and my HP OfficeJet software are 64 bit so I uninstalled my 32 bit Thunderbird and installed the 64 bit.

If the App Path/thunderbird.exe said: C:\ProgramFiles\MozillaThunderbird\thunderbird.exe Then that means you are using a windows64bit version of Thunderbird. So the registry in 'App Paths' will point to 'Program Files' and not 'Program Files (x86).

Did you then close down computer and restart computer, so it restarts scanner etc ?

Hate to point out the obvious, but on my system thunderbird.exe is located in

C:\Program Files (x86)\Mozilla Thunderbird

but you state the path is (for 64-bit TB)

C:\ProgramFiles\MozillaThunderbird\thunderbird.exe

with no space between Mozilla and Thunderbird. Is that a typo, and do you have the correct path in the registry?

Thanks again! All four strings now read: C:\ProgramFiles\MozillaThunderbird\thunderbird.exe. All programs are 64 bit. However, noticed that the string for my HP Scanner has a (x86) in it. Would that make a difference? I rebooted everything and get the same error message.

I do not have a space between Mozilla and Thunderbird in the string. Do I need one?

I do not have a space between Mozilla and Thunderbird in the string. Do I need one?

The string has to be the same as what it is on your computer. Open Program Files in File Explorer. Is it Mozilla Thunderbird or MozillaThunderbird?

I don't believe it! My problem was that I did not have spaces between Program & Files or between Mozilla and Thunderbird. It works without the (x86) in the string.'

Thank you, thank you, thank you for sticking with me through all of this. If you were in Miami I would buy you a drink!!!!

Good to hear it is now all working.