Motor revs but grinder does not engage.

No brand or model? Okay, general reasons why grinders clog up. Most common I've found is worn out burrs. The plates, depends on composition and usage. Metal plates last longer but not forever. If your grinding thousand pounds of beans don't expect it to last. I've seen massive grinders fail within a month. It all depends on two factors; How much and how fine. Large grind size will increase life and fine grinds wear the burrs out very fast. Especially Turkish settings. Fine grinds also generate a lot of heat. This can cook the coffee again and make it change in flavor. Heat also forces the oils in the bean to coat the burrs and make them dull out which causes more heat. Prolong grinding will also burn out motor.
* Worse case senario; Very oily beans ground to espresso fine. This is usually the case with 'local' roasters. Poor quality beans, extreme roasting (pushing the max on toasting limits), and extreme fine grinds for a particular roast. Fine grinding tends to work on dryer beans. Heavy moisture (under roasted or beans not aged enough to outgas and dry out) will gum up any grinder. Let your roaster know what your trying to do. Otherwise go with a name brand and correct bean for the flavor profile your looking for. Don't expect 5 star espresso from a cheap roast.
* Final, most likely worn burrs needs to be changed out. Off chance the motor is burnt out or starter capacitor needs replacement. If it is the motor or cap, then you need to review your grinding methods as grinder motors are usually tough enough to handle the range of grinds listed in the specs. burning the motor is a clear sign of abuse.
* Have your vendor look at the grinder. They will know right away what's wrong.
Aloha, ukeboy57

Humm, G-3 grinders. Okay what common problems I've come across:
* Wrong setting for grind on label. Usually means worn out grinder burrs. But this does not happen often unless you are using it to grind commercial amounts of coffee? It's a retail level grinder meant to be user friendly and simple to use. Say grind a bag of beans once every 10 mins or so even with customers lined up to grind there own. Running a G-3 constantly is usually done by upcoming coffee vendors whom are using it for small flavored bean batches. But expect the burr plates to only last 3 to 6 months. We used to change it every month till the boss bought a bigger pro grinder. (whew!)
* Out of calibration (for grind) This usually happens as soon as it's installed. Either the grinder got banged (Dropped?) around or the lock nut was not tighten down. If caught quickly then it's a simple adjustment. Left unchecked will wear out the burrs or crack the plate.
* Trips out breaker. This is common at retail stores as it's located in a shelf rack that really does not have the required outlets. Many times there is a brewer(s) connected to the same line. It only trips out when one or both brewers are heating and the grinder is running a very fine grind.
* Trips out breaker when grinding espresso or very fine grinds. Worn burrs or slim chance the grinder was miss calibrated (but you would catch this when first installed)
* Shocks the customer. Dry climates or heavy air conditioning will build up static electricity at the chute. There usually a small chain attached to the chute to prevent this. Attach a SHORT metal chain or thin cable to the metal case of the grinder and add a metal clip to attach to the coffee bag. Many use a chain and clip just short enough to keep the bag positioned under the chute. Note many coffee bags come with bag clips. Just make sure the clip and chain can't get stuck in the grinder.
* Not working. This is usually the on/off switch as it gets beat up the most. There is sometimes a safety micro switch under the chute to sense if there is a bag there. I've found may have been defeated.
* No power, check cord, breaker (GFRI) outlet, Plug prongs if broken off or bent.
* power but no motor hum. Tripped thermal breaker (usually a red button on side or back. Some models may have it inside on the motor itself. Call for service to check.
* Turns on but loud hum (may be hot too). Burrs stuck. This could be from adjusting grinder while grinding beans and adjusting to a fine setting. Grinding finer slows down the beans feeding the burrs. Large settings flood the burrs with a lot of beans. Adjustments are usually done when the grinder hopper is completely empty. If loaded and turned down from coarse to fine grind the beans already in the burrs get crushed and stuck between the plates thus locking them in. It may be possible to clear the hopper and open up the grinder to its coarsest setting to jog out the crushed beans. Otherwise call for service to have the burrs cleared manually.
*Finally check with your vendor if your still having problems.

Aloha! ukeboy57

If using Beans; it is set to fine and due to static it sticks - OR you have a blockage..

If you are putting ground coffee into a grinder; the static will be a bigger issue and in addition there is no weight from the beans to press the grinds into the burrs. A bean grinder is not ment to grind beans that have already been ground.

Get a better grinder and do not buy supermarket beans.

you must screw off the burr holder plate screw (in center) you will order one special screw, drill shaped, when the burrs roll it will mix and take down the coffee beans. That is solution i applied to many grinders. PS: beware the direction of burrs must be coordinated with new screw.

First, I'm not a Baratza tech, but I have worked on commercial grinders. You should contact your vendor for service.
*** The following is for information only ***
* check on line for your model parts manual. The diagrams will help you identify the parts needed and should provide instructions on replacing/cleaning the burrs.
* As you've figured out, cleaning with rice is not a good idea.
* Burr plates do get dull and needs to be replaced. Longer grind times and frequent adjustments to get finer grinds is an indication of dull plates.
* The oil in the beans used gets caked up under and on the sides of the burr plates.
* Heavy usage and long grind times will melt the oils and fill every part of the burr chamber and even get into the motor and bearings. I've found oil in the on/off switches and rotary switches.
* The burr plates must be removed and chamber cleaned of all oil residue and beans (rice too). Use a vacuum cleaner and stiff brush to clean. Do not use water or any liquids in the burr chamber. You can clean the burrs in wash water once it's removed from equipment. Dry thoroughly before reinstalling.
* The motor should turn freely by hand (no power!) with nothing hitting the sides or under the plate. If it's difficult to turn or makes grinding or whirling noise. Then the lower plate needs to be removed and cleaned. The motor bearings will need to be replaced if the motor does not turn at all.
* Once cleaned and assembled(without any beans) Power up and check the operation. You should have a motor hum without any clanking or screeching (metal rubbing metal) sounds. Stop and power down if you do. Motor bearings are bad.
* If you get nothing then check the switches. Oil probably got in them. Replace.
* Runs okay? Then set the grinder to a large setting (like drip coffee; Turn on and allow to run while you drop some whole beans into the hopper. Use 1/4 cup or less. This should grind through smoothly.
* Placing another 1/4 cup of whole beans. Turn on grinder again. Just hums without grinding? Power down. Replace motor starter capacitor.
* The capacitor is round and usually attached to the motor like a 'hump' on the side or near the top. If you didn't take it apart then one of the wires in the switching side may be miss wired or loose. Check both for loose and correct wired. Careful around the capacitor as it may still have a charge! The capacitor is used to kick start the motor with it's heavy burr plates.
* If your still having problems with low power. Check the motor for burnt smell as you may have overheated and fried the motor. They usually have thermal resets, but if you kept forcing the reset to keep grinding then the motor is defiantly burnt out.
* Final; if everything is working but your not getting the fine grind setting (you should at least get espresso setting but not turkish) then the burrs are gone. It will only be good for drip coffee.
Aloha, ukeboy57

PS I found a cute video on how to clean the burrs (frequent cleaning)
https://www.bing.com/videos/search?q=baratza+virtuoso+grinder+cleaning+burrs&&view=detail&mid=41DCCF0EB0CACFEA9E4841DCCF0EB0CACFEA9E48&&FORM=VRDGAR

I would suspect a log in the outlet shute where it goes into the grinds hopper. Clean it out and then turn the hopper to the coarsest setting to clean it out all together. Coarse grinds are a very good cleaner.

Lets do this, remove the bean hopper, and make sure there are no beans in the burr chamber. Then looking down at the collar with the numbers back up screw if there is one on it. Now if memory serves me right clockwise is coarse and counter is fine. Look down in the burr chamber, notice the nut in the middle, turn it with your fingers that will move the bottom burr, if burr turns freely we will move on if not plug in grinder and let it grind out remaining beans. With beans gone unplug grinder, then turn collar towards fine until you cannot go no more, now try turning nut it will be hard if not impossible to move, turn collar towards coarse until you can barely move bottom burr with fingers, you will hear and feel the burrs touching, that will be our bottom setting. Now pick a spot on the grinder you can use the small notch in the middle, count out 16 notches towards coarse and turn collar to that point. Use the notches around the collar not the ones on the top next to the numbers. Your grind should be almost perfect, depending on blend and machine you might have to adjust 1 notch to the left or right after testing.

Hi Your burr is not locked in. You need to remove the beans from the hopper. Remove the hopper. Remove the burr. Turn the grinder upside down over the trash can. Put the burr back in only make sure that the burr is down. Install the bean hopper and when you turn the bean hopper it should move the burr. Then you can adjust your grind. Make sure that the grinder is running is your going to a finer grind or you could break the grinder. You can turn it to a coarse grind any time.

Rotate the bean hopper counter clockwise until it stops. Lift it off. Remove the outer burr with the 2 wings and clean under the burr. Clean the opening going to the chute for ground coffee(inside where the burr was).
Install the outer burr. Install the bean hopper. Rotate the bean hopper to the French press grind (coarsest) and operate the grinder. This will clean the burrs and the passages. If it starts to clog, repeat the last part to clean the burrs and passage. It must be grinding to go to a finer setting, but you can go to a coarser setting any time. Another thing. Turn the grinder upside down (empty) and rotate the bean hopper back and forth to clean the threads of the adjusting burr..

This fixes almost all the "beans will not feed or beans will not grind" problems caused by coffee bean dust packed in the burrs. Oily beans cause this problem more fequently.
a. Pour all the beans out the top.
b. Open the settings up all the way and see what else can be poured out. Use your shop vacuum to **** grounds out the spout and backward out the bean bin.
c. Pour in some instant rice and start grinding. Reduce the grind to a small setting like six and then open the settings all the way again. (The grinder will not start at a low setting with the rice in it. If you let it stop, open the settings to about 16 before trying to restart.)
d. Pour out the rice and vacuum out the ground rice.
e. Adjust the grinder to your favorite setting and try a coffee grind. Grind until most of the rice dust is expelled (any remaining trace of rice dust will not affect the flavor of the coffee).