I have switched from Thunderbird to Postbox as my email client recently as I wanted to see if it was more stable and crashed less often than Thunderbird. I use an email desktop client primarily because I run multiple separate Gmail accounts some are business app emails like my dragonblogger.com one and some are my personal accounts. The problem is the web based gmail has issues switching back and forth occasionally still but I like the email threading of Gmail that Thunderbird doesn’t have.
Postbox was worth a try which has a very Thunderbird/Outlook 2013 style interface but with email threading like Gmail and integrates with Social Media as well. One thing right off the bat that got my attention was how Postbox handles unread messages by default. Instead of bolding unread messages like Thunderbird or Outlook Postbox would just add a little blue dot to the left of unread messages.
This means all messages were always bolded and only the blue dot was your indicator that it was unread. This was hard for me to get used to, so I found a configuration setting in Postbox that let Postbox bold unread messages so that Postbox was like Thunderbird in that unread emails were bold and read messages were not bold anymore.
Here is a video tutorial to make Postbox bold unread email
Or else here are manual instructions to configure Postbox to make unread emails bold.
Step 1 – Click on Tools –> Options
Step 2 – Click on Advanced Tab / General –> Click on Config Editor
Step 3 – Acknowledge the statement about voiding your warranty
Step 4 – Type vertical.bold and press enter in the filter bar
Step 5 – Double click the pb.thread_pane.vertical.bold_unread so that the value is true.
Step 6 – Close out of config and options
Now all of your unread emails will be bold and have a blue dot to the left of them and read emails will now be non-bold so you basically were able to make Postbox look like Thunderbird or Outlook when it comes to handling unread emails in Postbox.
So far Postbox seems to be faster at syncing with Gmail and seems more stable than Thunderbird while still allowing a Wisestamp plugin. Have you used Postbox? It is free for 30 days and after that it still is a minor cost at $9.95 which is a fraction of Outlook 2013 for example.