What to do if a "System Error" occurs with a Lumix camera

The entire Panasonic Lumix line, over a span of several years, has been stained by a "System Error Zoom" flaw. I have repaired many Lumix cameras, because I believe them to be exceptionally well-engineered and ultra high quality builds, compared to some of the other current cameras that are popular.
I won't name any brands.

Before I discuss possible solutions I'd like to mention WHY so many people end up with malfunctioning Lumix cameras due to "System Error Zoom" failures.
The most common etiology is because the lens extends such a significant distance, partially because people are enthralled with "Super-zooms". The downside is obviously if there is anything that obstructs the lens extension, such as the camera gets turned on while still in the camera case, or anything is in front of the lens as it is extending, such as the User's finger or any object, the tiny gear that drives the extension process can lose gear teeth. Or the tiny Zoom Motor, which is quite weak, simply gets overloaded and burns out.
That is simply the end of that camera. It is DNR, Do Not Resuscitate, because it is far too expensive to have it repaired by Panasonic.
Lumix cameras that were once expensive are often on sale on eBay for 10 dollars, because they have System Errors, and people are cognizant of the expense of repair. Today, for example, on eBay there are 4 ZS19 and ZS20 models on sale all together as a lot for 20 dollars. 5 dollars apiece, for 4 400 dollars cameras.

Another way that Lumix and similar Panasonic cameras get destroyed is the User is holding the camera improperly, and when the User either turns the camera on (which always starts the lens extension), or is already taking pictures and zooms the lens out, the User has a finger placed in such a way that it obstructs the lens extension.
You can visualize that even if the finger is covering only one small part of the area where the lens is headed the barrel will be skewed toward that side, and that is all that is necessary; the barrels are barely more than cigarette paper thick, and they deform quite easily. The resulting friction of any of the multiple lens barrels grinding against each other overpowers the tiny Zoom Motor.
The other major causative is obvious, a foreign body of some type gets embedded in the system of lens barrels and inhibits the barrels from smoothly extending. It takes only a tiny tiny piece of lint or dust or such to cause permanent damage.
There are several lens barrels, in a type of Russian Matrioshka Doll arrangement, one fits with merely microscopic tolerance inside another and another and another...and they must all extend without any resistance in order to operate properly.
The thing I see Users do repeatedly is keep a camera in a bag or case. Dust or dirt or other foreign matter collects at the bottom of the case, and easily finds its way to the lens barrels.
Or people often put some form of fabric into the case with a camera, a lens cloth or business card or a label with the User's name or a handkerchief or such, and lint from any fabric will stop the lens from extending.
If a Lumix gets put into a desk drawer for a brief time, it will be in enough dust to ruin the lens assembly when the lens extends after the camera being turned on.
So imagine someone on vacation, with a camera in a camera case which is in a suitcase, which also has shirts and pants and socks. Goodbye, Lumix.
I never use a camera case. If I need to enclose a camera for some reason I simply use a large ZipLoc plastic bag. With a desiccant pack.
OK, now WHAT TO DO.
First, I recommend you ask Gravity for assistance; hold the camera with the lens pointed straight down. Then turn the camera on and off and on and off and quite often the reduction of the effort needed for the lens to extend because Gravity is helping will allow a causative foreign body to fall, or get powered out by the passing lens barrel.
I often have had great results after simply putting a vacuum cleaners small hose extension over the lens assembly and vacuuming while the camera is off and the lens assemblies are all fully retracted.
That has enabled many Lumix cameras to begin working again.
(I personally do not advocate the use of air blowers of any type because that simply drives any foreign body(s) deeper into the lens assembly.)

As a tangent: If you are considering the purchase of any used Lumix I urge you to be certain you can examine 2 closeup photos of the camera with 1) Lens fully extended and 2) Lens fully retracted. An unscrupulous Seller can post pictures of a Lumix with a retracted lens and not mention it will simply not extend and is useless.
And insist on a photograph from behind the camera while TURNED ON and the LCD screen IN FOCUS and clearly visible.
A Lumix with a System Error will display "System Error Zoom" or similar in the LCD screen...so if you see a photograph of a Lumix that is turned on and that is not displayed in the LCD you have at least zeroed out that concern.

Also:
I always urge people to change SD cards, as sometimes a poorly formatted SD card gives the camera problems when it tries to read the SD card when it gets turned on, and that halts the turning-on process and results in a System Error.
And I encourage fully charging the battery, or putting in a different battery, if the camera has been used often and the battery may have weakened.
If someone purchases a used Lumix that is 3 years old for example I think spending 10 dollars for a newly manufactured battery is wise.
TLDR:
1. Camera was turned on while still in case or when something was in front of it.
2. Camera was held improperly and finger was in front of part of the lens as it was extending. (Also occurs when the User is taking a Macro photo and gets to close to the object)
3. Camera was kept in a bag or camera case or a drawer or on a shelf or in a suitcase etc etc etc and lint or other foreign matter had collected, and fouled the exquisitely delicate barrel-lens system.

Good luck. I hope I have helped.