I have had a similar issues as described in the thread below for the past year or so. I have used Quicken since 1996 and my .QDF file is currently 216MB. I did some testing today and found the cause of the slowness, at least for me. On the Quicken Home screen there is a Dashboard. This seems to be the culprit. Launching Quicken on my Win10 PC to the Dashboard is very slow, 54 seconds. Everything I do is slow (download, transactions, etc). However, if you click the gear icon in the upper right it gives you the option to select the Classic View Dashboard. The Classic View gives you the option to select other views such as Account Summary and your custom views (select any view other than Dashboard and you can customize it or add a new view). I used the Account Summary and my custom view for the tests and got similar results. These results vs using Dashboard are summarized below:
Launch Quicken: using Dashboard 54 seconds, using Account Summary 11 seconds
Run One Step Update: using Dashboard 4 minutes, using Account Summary 28 seconds
Enter transaction into register: using Dashboard 38 seconds, using Account Summary <1 second
As you can see, there is some sort of issue with Dashboard as it results in significant slowness. Try using the Account Summary Home view and see if this resolves the slowness you are experiencing with Quicken. Also, make sure your Edit|Preferences|Startup option is set to Home and NOT Dashboard.
I tried to add to this previous discussion but it would take it for some reason.
I am hoping a responsible real live "Quicken" person will read this. Today, I search posts with the word slow. There are many posts. All along, every time this question gets raised including yours truly, immediately the finger gets pointed to the users computer. That is freaking shame. The problem is with Quicken. I believe that this is a problem caused by a Windows update that Quicken failed to adapt to.
My significant daily experience with Quicken goes back to DOS 5.2. I have never had persistent slow performance, hour glass wait, extremely slow update issues until the last year. Every time I contact Quicken they try to point the finger at my computer. I hope that all of you you who have posted similar issues only to become frustrated with Quicken's apathy will chime in here. Maybe we can persuade them to fix it.