Double click the profile in RM and make sure you see a little "headphone" icon in front of it in RM. That will let you know the profile is loaded to be auditioned (played).
Arrow Keys work great also once you are in the list of rigs. For me it is easier than trying to grab the mouse and click.
Just for giggles, did Kemper have you run RM as an admin? If for some security reason RM has lost access to certain directories maybe it just crashes??? Worth a shot.
If you right click the Rig Manager program icon from the start menu, your desktop, or explorer you get the RUN AS ADMINISTRATOR option.
May need more information.
1) Has it ever run on this PC?
2) Did it run for years and all of a sudden start crashing?
3) Do you let Windows auto-update (most everyone does)? Did RM stop working after an update? Most applications run on runtime libraries that Microsoft updates randomly.
4) Have you tried starting RM with no unit connected? A different USB cord and/or port?
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CORRUPT FILES MAYBE??? DANGER: PROCEED WITH CAUTION
RM stores its user data in C:\Users\YOURWINDOWSACCOUNTNAME\AppData\Local\Kemper Amps\Rig Manager. After uninstalling RM make sure this folder is empty. Maybe there is a corrupt data file that is crashing RM.
NOTE: This is where your local library files are stored!!! Make a copy/backup of the files in ..\Local Library before deleting everything.
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I have seen rare instances when Windows updates itself it will lose access to the USERS directory. Since you have uninstalled and then reinstalled, this is probably not the issue. This issue would present more like RM stops working after a Windows update.
Are you listening to the Cab the same way you are listening to the Altos?
Hi freqs are directional. If you listen to the cab pointed at your ankles and the Altos pointed at your head, the Altos will sound very harsh since your profiles may be tuned to the cab on the floor. Meaning you wont hear the highs on the cab since the highs are all going at your knees/ankles so people tend to tune the profiles very bright/harsh. Once you have the Altos pointed at your head, you will hear ALL of the extra highs you added to the profile.
As Kellerblues said, most people here will suggest the OUTPUT menu Hi Cut filter.
Bruh! Like I know right!
I'd use just a touch of room reverb. Less is more, but it works great
I was going to say the same thing. If you worry about changing the tone too much (Chorus, pitch, etc) then add some really small room reverb. Whats great about the Kemper is you can EQ the verb settings so they emphasize the right part of your sound. And as musicmad said, less is more. You dont want the "I'm in a tube" or "in a toilet" setting 
My take is LP will be modeled filters. The whole profiling process figures out how the tubes are reacting to the input. So there is no need for the Kemper to try and model those components.
The simplest thing to do is model the EQ controls from the real amp. This is important because those EQ values are not the same the Kemper uses now with its fixed value EQ.
Add to this the fact most amp filters interact with each other. Changing the mid or bass may actually change how the treble sounds. So boosting the 120 Hz (bass) on a graphic EQ will give you more bass around 120 Hz only. Changing the bass on an amp may also add some 900 Hz because you are altering the circuit and the bass components are part of the mid components. They feed into each other.
The current Kemper EQ can only give one type of EQ curve. The new EQs being added will give you a lot of alternatives. And they will be some what predictable if you know the amp. You could already get very close using the Studio EQ. But it would take some knowledge, testing, and the values will NOT interact like the real amp. With LP it is a one click operation.
Modelers try to nail down all of the gain stages and their interactions. I predict the Kemper will stick to the same single stage gain structure it has now. Just use more accurate EQs.
2. Reduce the low end before the gain stage. This is sort of what the DEFINITION does. I like to run an EQ as the first stomp.
Working on my VST, I found a good start for low cut is around 150 Hz (crunch) and move it up as the gain increases. Then add bass back after gain stages.
Just checking, how are you listening to the Kemper?
I normally play thru a 100 watt stereo into Behringer 2031P 8" monitors. The tweeters are very flat sounding. I dont normally play loud. And the overall sound of the Kemper is fine. But it does not sing or have much treble presence. It sounds a bit muted.
While working on the VST, I am on my programming PC which has Edifier 1280T 4" speakers. These speakers are not flat. There is a lot of low bass and crisp highs. Guitar sounds amazing on them. When playing the VST on these speakers it sings and has amazing presence like you are next to the amp. Really fun to play on them.
I have not spent enough time with the VST on the Behringers to get a feel for it.
Today, I pulled the Kemper up to the programming PC and played thru the Edifiers. It sang fine and was a blast to play. So some of the singing tone must be vibrations and feedback from these speakers. Even though I am not playing loud at all. But I was blown away by how much better it sang.
I keep making these posts about how important the crossover and tweeter are for guitar. The Edifiers sounds amazing. The Behringers... not so much. They of course have better bass and can play at much higher volumes. But the presence and sizzle of the tweeter is MIA.
I recently repaired an old Laney ProTube 50. It has a very nice Tube sound on the clean channel. Was testing pedals today on it. I will eventually test out the Kemper on it. I usually play thru a custom 2x12 cab I made with varying speakers in it. They get rotated. Eminence, Bugera, and Celestion 70 80.
I doubt it. I'd guess it's the profiles you choose, the power you use for the speakers or your monitoring setup.
I purchased the profiles I heard people play and they dont sound similar to me at all. Now that I have written the VST stuff, I am very tempted to sell the Kemper. But I love making profiles. So I still mess with it all the time. I also want to try some other monitoring situations, just been too busy to try it out yet.
My real point was how so many of the non Kemper users have all these pedals cables and tube amps that a Kemper alone would do a better job at. Thus "Why not just a Kemper"? I haven't heard a single Rig rundown with amp and pedals that a Kemper wouldn't outdo in every way in my opinion.
I am not very smart. But in writing my VST, I have some insight.
My personal Kemper does not sing like a tube amp. My old POD HD has a singing tone on one profile. That is why I constantly feel there is something wrong with MY Kemper.
My VST is centered around a generic distortion pedal. I have the signal go into a bandpass filter centered between 600 and 1400 Hz (700 Hz is typical). You can control the Q of the filter. This little "transistor" amp pedal model "sings". If I hit an A note (10th fret B string) it will slowly change the pitch up an octave as the string decays. I do not get this type of thing from the Kemper on any profile. Even ones I have made from the VST that sing. And the singing is the main reason why I bought the Kemper. Seeing Herman Li get great tone on his Twitch stream.
I think you need to do this filtering before the distortion stage. Which would require a stomp/EQ in the Kemper. Which I have tried but have not had success yet. Still working on it because Herman does it, so it must be possible. Assuming he is not using some other pedals external, which he may be doing.
MY POINT
For most people, they can grab a pedal and a tube amp and they are done. It works great and gets them over that 2% improvement hump with no work or knowledge required. Since they may not understand what they need to do to get the right tone, they have to fall back to rumor and legend buying whatever the magic bullet is.
Those of us who have the knowledge or just like tinkering prefer the day to day repeatability and ease of use of the Kemper.
I haven't had much luck using a dynamic mic...
I got a Behringer C-1 low grade dog food condenser mic for $19 on sale ($45 normally). And it is the best guitar mic I have ever used 
Most of my profiles have C1 after them.
ON TOPIC
Since you can press REFERENCE AMP, you should be able to dial in the amp sound with music before profiling? But that would still be song dependent. So maybe not much help overall.
Besides, I only own one other OD/Dist pedal.
Time to up your game! I am not a pedal guy at all and I several.
Just kidding, I never use pedals. But I do have a few. Notables are:
- a Nobles OD because someone suggested it. Pretty cool. Drives a Metal Zone really well.
- Wampler Dracarys. I wanted something heavy and I wanted to give Wampler money. It was basically a donation to his cause of making awesome pedals. Super cool guy.
Glad you got it. Cant wait to hear all about it and maybe get some profiles from ya! We need content while we wait for Liquid Profiling
Geetar #3 arrived in fine shape. I also got a can of spray paint and solid black single coil pickup covers on #1. The painted stripes look horrible, but the vibe is good.
So 3 guitars. (pictured in order of 2,1,3)
#1 has an old Ibanez/EMG pickup, can of paint, and plastic pickup covers: $69+$10+$12=$91
#2 was $55
#3 was $71
Total Price: $217 + tax + the value of the old EMG that was sitting in a drawer.
I was talking to a buddy and we were reminiscing about when we started out, were broke, and had no gear. Where was this stuff then? Kids these days , they have it so easy
Great list so far 
I like the one that mentions being louder. Every change that makes it louder always seems to sound better no matter what.
Our brains adapt so fast. Thats why we can listen to music on massive perfect speakers or an old hand held AM radio. Our brains convert it to music and balance it out. But when we go from one sound to another real fast, our brains go "bruh, this aint right". It takes you shutting off your brain and playing for like 5 or 10 minutes before the small EQ differences get adjusted in our brains.
As V8 said, that is why a Kemper is so good. You logically know it is right. It has to be your ears or your amplification that have changed.
But man is it hard to just let it go and not start tweaking. Is there a name for this? Like we have GAS. Is there some other slang for constantly tweaking knobs?
An IR is just a sound file like any music you may have. The WAVE file format is used because there is no compression. No compression/decompression means the file is perfect and not messed up just by saving. IRs are almost always MONO.
Any Audio Editing software will have EQ options. I always use Goldwave (my personal favorite). But there are many many options.
WHAT IS AN IMPULSE RESPONSE
When you play an impulse(Left) thru a speaker, the impulse is turned into a softer spike followed by a lot of oscillations (right). The oscillations are the effect of the speaker trying to move, its vibrations, and vibrations of the cabinet itself.
The image on the right is what your IR waveform will look like in an audio editing program. Notice the sharp spike and small vibrations after. Also notice there is only a small amount of time before the impulse starts. This delay creates a delay or lag in the playback of your IR. You do not want a lot of time here. Smaller is better. This delay may get removed when the Kemper converts the IR to a CAB, but smaller is still better.
1) Make a copy of the IR/WAVE file.
2) Open the copy IR/WAVE file in an audio editor.
3) Apply an EQ to it just like you would music.
4) Save the edited IR/WAVE file.
After the EQ, make sure the IR still has a spike to it. Some filters destroy the phase response of the frequencies. You will get best results if you do not destroy the phase response. Try a different filter EQ in that software.
The IR usually has a spike followed by small ripples. This spike sort of determines how loud the IR is. If you edit an IR and it gets all smeared, the spike disappears and the resulting IR may be much louder than the original. Especially if you NORMALIZE or MAXIMIZE the volume after editing.
Goldwave note: Spectrum Filters works good in GW. Graphic EQ will destroy the phase and mess up the waveform.
TRICKS
1) In your audio editor, change the pitch of the IR. This lets you make the speaker sound larger or smaller. Larger (lower pitch) usually works best. You will get a thicker heavier cabinet sound.
2) Apply compression to the IR to alter the frequency response and alter volume.
Goldwave note: The default Pitch Change effect works great. Do not select Preserve Tempo, which uses FFT and can mess up the IR. Or experiment and use the FFT method, but you will need to edit the results because the spike can get moved.
DEEP DIVE
The IR is a plot of the sound echoes of the original impulse. If the IR was made very long in time, it could be used as a reverb. In fact, a guitar IR is basically is a very fast reverb simulation. The longest IR files the Kemper uses are 2048 samples. At 44.1 kHz that is a very short amount of time. Approx 47 mS. Not enough time to make a cool reverb. But you could make a fast slapback echo
Since the IR is a plot of the echoes, the IR is reproduced in software by simply multiplying each guitar sample by the IR. In essence playing back all 2048 echoes at once. Since the echoes are out of time from the original pulse, they phase cancel and create a time based EQ. That is why you do not want to apply an audio editor EQ that smears the phase response. It may alter the final IR sound a lot.
CAVEAT EMPTOR
My brain is small. I know just enough to be dangerous. Read what smart people have said about IRs, because some of what I posted is probably wrong.
To get an IR out of a hardware unit you have a several options:
HERE ARE SOME FREE OPTIONS I HAVE USED
1) Profile the unit using a clean tone. No amps, effects etc to just get the frequency response of the IR. However, the Kemper may see this as having no IR/CAB so you may get nothing but a clean amplifier profile with no CAB.
2) Send an impulse into the unit and capture the output. An impulse is a single sample at some high volume. All other samples are zero. The output of the device will be a waveform of the IR. You can then drag this into the Kemper using Rig Manager.
3) Do a frequency sweep of the device. I have used ROOM EQ WIZARD with good results. It is a little complicated getting the IR out of REW. You will need a waveform editor and some instructions. But it lets you really see what the IR is doing to your sound. Very cool.
When I do this stuff, I am on a Windows PC. I always use Goldwave audio editor.
For method 2, I create an impulse file in Goldwave and save it. I then play the wave file in a loop in Windows Media Player and record the output of the hardware using Goldwave. Find the best looking IR pulse, clip it, and save it.
I think the Kemper normally uses 44.1 kHz files that are at least 2048 samples long. You can try saving in 16 or 24 bit depth.
TIP: You can edit the IR wave files to further tweak the EQ if you want to.
Bottom line. Do your updates. Peace
I think this highlights another point....there are times when I think my guitar sound is amazing and other days sounds pants....
I have been writing a VST (tired of saying it), and I dialed in a certain sound that is close to perfect for me for heavier stuff. Its that magic setting that no matter what you play, it sounds amazing. So you can just write riff after riff all day long.
And 1 out of 4 times I use that sound, it sounds like trash to me. 
In my case, my monitors are adding a touch of distortion. So their volume is key to getting it to that perfect spot. But some days it still just sounds bad to me. On those days I just do what V8guitar says by putting my head down and just playing.
I really like Hudiluma idea about switching to a worse sound and coming back. This is a great idea.
