Postbox is a great email client. But the great things can face challenges too. Lucky for you, none of those are unbeatable. There are things that you can do, either individually for a single problem, or just fix one thing to get rid of all of the issues together.
Postbox Troubleshooting Tips
If your Postbox crashes too frequently, or doesn’t start at all. If it performs searches too slowly. If some of the folders appear empty. If attachments are missing. If you can’t find something that you know exist. If you are having any of those issues, you can start troubleshooting using the tips given below. You may not have to go through all of them. If you are lucky, the first one may do the trick. Worst case scenario, you might have to try few more until the problems are fixed.

Reset or Rebuild
You can also reset or rebuild your IMAP database and search indexes. Try this method if the problem occurs mainly while you search for a message. Go to the Help menu –> Troubleshooting –> and choose “Reset IMAP Mail Database and search Indexes.” This might take time but by the time it is over, you will have a very smooth running Postbox with no issues.
Software Applications
There can be few applications that may be in conflict with Postbox. Most of the times, it is your antivirus that is mis-firing as soon as Postbox is launched. Your internet security programs and even disk utilities can stop Postbox from functioning smoothly. Try uninstalling or disabling them to see if that’s the case. You can then add Postbox as an exception to these programs to let them know it’s fine to allow Postbox to function.
Disable Add-ons
Postbox doesn’t have a safe-mode feature, but it lets you disable add-ons, which is the major function of safe-mode in many other email clients. So it’s kinda same. Go to Help Menu, select ‘Troubleshooting,’ and choose Permanently disable all Add-ons. Restart Postbox.
Most likely, it would make Postbox running like a summer breeze. You can then delete the suspecting add-on and restart Postbox again. If it gives you the trouble again, the add-on you removed wasn’t the wrongdoer. Try deleting some other add-on that might be causing the chaos. Repeat the process. Hopefully, you will get to the one causing problems.
Use Safe-Mode
Try using Safe-Mode in Mac OS X or Windows wherever you are using Postbox. Postbox itself doesn’t exactly have safe-mode (it has something similar that is explained below), but by restarting your entire computer in safe-mode can sometimes take you to the root of the problem. Many problems are caused by the conflicts between Postbox and other applications.
Recreate Profile
If nothing else works, try deleting your Postbox profile and creating a new one from scratch. Obviously, this is going to take very long to finish, most likely if your database was huge. But this solves almost all problems for almost all users. You can also choose not to delete your old profile and keep it running alongside the new one till the time the new profile is properly built up with all your mails and everything. You can later delete the old one and migrate all of your settings and stuff to the new one.
Other Conflicts
Postbox recommends creating a new MacOS account if none of the above solutions work (because in that case, it is likely that Postbox doesn’t have any problems; it’s your computer that does). It is quite obvious why this solution would work all the time; it resets not only Postbox but also your MacOS entirely. It will remove any conflict you might be having with other programs.
Hopefully, the above troubleshooting tips will let you start using Postbox again without having to constantly being annoyed by the issues and problems you might be facing.
Resolve Issues With Postbox
The last thing that you can do is contact Postbox support. You might have to wait to get a response, but the support can be helpful and will help you see things that you might have missed during troubleshoot.