I know I've posted about this before but I can't find any prior reference in the forums (fora?). But I can't be the only one with this issue. The "scrub" tool just doesn't work. At first, there's no response, then a notification"The audio engine has stopped unexpectedly." This happens ONLY when ProChannel tool(s) (on any channel, either track or output, are active. This is true with existing projects, as well as a test project with only one track. Trial and error... for the single track test project, if only ONE ProChannel tool is active, then scrub works normally. If TWO are activated, then it balks, and eventually, Sonar crashes entirely.
 
Adjusting ASIO buffer size makes no difference, nor does bit depth, bit rate, signal complexity, you name it.
If ProChannel tools are activated, scrub just doesn't work.
 
I've been using Sonar since WAY before it was Sonar, though Pro Audio, and even simple Cakewalk days, but this has got me stumped. I'd be really happy if anyone could give me a clue on this... it really makes editing difficult, and it really embarrassing in front of studio clients.
 
Windows 10/64 Professional, Intel Core i7 @3.4GHz, 16GB RAM, 1TB SSD HDD
Sonar Platinum 23.9.0 Build 31
Scarlett 18i20 (rev 1), 44.1kHz/24 bit

A few things to check is:
- The Pause/Break button on your keyboard.
- Try toggling the FX button (F button) or possibly even the PDC button (E button) to narrow down a CPU issue.

 
I've had troubles in the past myself with Scrubbing. not sure what it is but sometimes it works fine, other times it stalls out. It hasn't happened in a long time for me since I upgraded my PC.
 

This PC is specially made for audio -- it looks like we have a similar setup. Screaming fast PC... and there are NO problems in SP other than this!!!! Strange, isn't it.
 
But thanks very much for the "F" button tip. At least it gives me a workaround. It's really hard to edit complex tracks without being able to scrub.

BTW... just ran update and now am using SP 23.10.0.14 (2017x10) x64... still same issue, though.

I'll double check it again in a bit

Interesting... the FX defeat doesn't work for scrubbing the entire track. In fact, it just went quiet, then as soon as I would re-enable the FX, SP would play a part of the track, then stop as if I were scrubbing... then crashed the program.

I tried to reproduce this problem on my machine running Sonar Platinum 2017.10 x64 and Win7 x64 with multiple instances of the ProChannel active and could not get the DAW to fail with both global FX enabled and disabled.  The scrub function works as expected for me using both the J key and mouse method and the scrub wheel on my Mackie d8b.  I'm sorry that this doesn't help solve your problem but at least you know its working for some folks.

Same as bitsync
I also tried  J key and mouse method and the scrub wheel on my Mackie MCU.
Both are working well.

I never use the scrub tool. Today I remembered reading this thread and tried it out. Locked me up. I had to use Task Manager to close Sonar (2017/10) and reboot to open back up. It's been a long time since I had to do that.
 
Since I don't use the tool, I won't be rolling back but I definitely think OP should start a thread in Problem Reports.
 
i7-3770 @3.4,32GB W10 Pro 1703-15063.674, NVIDEA GT730, Antelope Orion 32+

First time I tried it, too.
 
If 'j' is on and I try scrub on the timeline, the cursor jumps sluggishly instead of moving smoothly and I get a soft explosion sort of sound when it settles down.
 
But no lockup, no crash. Sonar stays up.
 
Latest edition, Integra-7 as audio interface, Win10 on old, old 8gb RAM laptop.