Sounds like it could a system problem. Could be virus protection software?
Too many operations and services running in the background?
Bottle necking caused by not enough or
good enough or mismatched RAM memory card sticks which can't be run in "Duel Channel" mode which your motherboard was designed for and needs to run in for maximum performance efficiency?
Not enough CPU power or not enough buss speed, or not enough or ill configured bargain basement RAM maybe OK for running Microsoft Office and streaming video from the internet, but in my experience ANY one of these conditions always been high on the list of trouble makers causing "computer brain farts" if you will, that happen at the most inconvenient times when put under too much memory intensive pressure(s) which are easily compounded and intensified in the heat of the moments of inspiration of computer based digital content creation.
Is your audio/MIDI interface(s) to small, slow, old, and outdated to handle all these operations you're throwing at and through it?
Are the ASIO drivers up to date and officially support the OS you are using? This has got to be the #1 most over looked trouble maker there is.
I look back with great fondness that's very close to love at my beloved MOTU 8, M-Audio Delta 1010, and UAD FX card.. I would have NEVER orphaned either one of these truly awesome PCI audio devices, but the vendors orphaned them in favor of USB, than motherboard vendors orphaned PCI slots in favor of PCIe, than Intel and AMD each through in a couple of tweaks and fastballs than Microsoft tries to readjust and tweak to innovate and accommodate everyone and all to the point where computer configuration and memory management are nearly (and I use that word loosely) nearly automatic with the HERCULIAN task of trying to please everybody without hurting anyone.
Nearly impossible because not all computer systems are the same, quite the contrary, and all software and hardware components are seldom all kept up to date...
Are you using hacked USB drivers to run your 7 year old MIDI keyboard with Windows 10? Hmm? Trying to out smart and fool Windows? Do you believe ASIO4ALL are actually ASIO drivers?
Well DON'T. ASIO4ALL might be OK for fooling your DAW into thinking the little sound chip built into your motherboard is actually a real standalone audio interface with it's own AD/DA converters and clock source, but nothing beats the real thing for the lowest latency and most stable performance.
Instead of using hacked drivers, try something simply unplugging the USB cable for your MIDI keyboard controller from your computer and plug it into a common cellphone charger for a power supply. Do not use a USB port from your computer to power the MIDI keyboard controller because Windows will forever search for drivers and cause unwanted latency and instability. Using a cellphone charger for a USB power supply stops that problem.
Hook your MIDI keyboard controller up to the computer with old school 5 pin MIDI cables, for trouble free operation that's been around for decades.
Just make sure you change/configure the MIDI I/O ports on your MIDI keyboard controller from USB port to the standard 5 pin dyn port and you are good to go using Cakewalk's ACT for customized MIDI mapping settings.
Some of these DXi and VSTi synths, especially sample based VSti synths like Addictive Drums and Rapture Pro can use enormous amounts of not only system memory, but CPU cycles which it has to share with the OS and DAW and added audio plugins. Using 3rd party hardware and software like VST and VSTi plugins can and will ADD to the problems, especially if your DAW is not listed as specifically being supported by the 3rd party vendor.
But even with a highly tuned workstation with gobs of memory has it's limits, especially during mixing and editing sessions when trying out or tweaking different audio plugins, changing and swapping out VSTi plugins, and forgetting to "SAVE" your work every time you make a serious change or series of changes for too long
is going to crash your DAW. That being said, you don't have to bounce down synths with SONAR or CbB, simply "freeze" them and let the DAW do it for you.
You can always simply "remove the audio track" from the synth's folder before deleting the synth, or copy and paste, or drag the audio track after freezing to another audio track that you have normally bounced to.