I spent a few hours last night trying to get the Softube Modular VST working with Reason 10 on my new mac. After searching the web, I couldn't find my answer. I submitted a ticket to Propellerheads and they got back to me the next day. While they didn't provide the answer I needed (well, not directly, anyway), they did lead me to the correct answer.

Softube modular gets installed in the correct VST folder on my iMac, but it gets installed in a Softube subfolder. It seems Reason doesn't look in subfolders when searching for VST plugins. All I had to do was copy the Modular.vst file from the Softube folder into the parent Library/Audio/Plug-Ins/VST folder.

Here is what my folder looked like before:

I double-clicked into the Softube folder:

Then I selected both files and pressed Cmd+C on my keyboard. I then navigated back one folder and pressed Cmd+V in the /Library/Audio/Plug-Ins/VST folder to copy them there.

Once I restarted Reason, the VST plugin showed up in my instrument list.

Problem solved. I spent a lot of time wondering if my license wasn't working properly (Softube uses the iLok licensing system). I was also unsure if the plugin was 64-bit or even compliant with VST2. I was able to launch the plugin and use it in Reason.

Since Softube Modular was one of the main reasons (heh) I updated from Reason 8 to Reason 10, this made me feel a lot better about my decision.