Will not work

Solution #1: Cold Reset
The reason it tells you to REMOVE AND REATTACH BATTERY is not that the
battery is bad, but that removing all sources of energy (battery and power
cord) causes a COLD RESET. When you use the unit's on/off switch, parts of
the camera are still receiving power and so you do not get the benefits of a
COLD RESET. Just like your car; turning the ignition off will still power
the clock and radio. You have to completely remove all power. If you are
lucky, the camera will reset itself and start working again.

Solution #2: Awareness of Humidity
It seems older units would issue the same SAFEGUARD MODE error message for
more than one problem. For example, older units do not tell you that they
are shutting down for an hour because they detected high condensation, or
moisture. So you play with the camera, remove the battery, reattach it,
remove the tape, reinsert it, stand on your head, pray to your god, go to
the bathroom, and voila! The camera is working again. It was nothing you
did, just that the humidity went down enough for the unit to start working
again. So consider high humidity as a possible source of the problem. If it
is a rainy day, or you are near the sea, you might never get it to work that
day in that location.

Solution #3: Head Cleaning
If you have never used a head-cleaning tape on your camcorder, you might
give that a try. Mine has come back to life a few times by doing just that.
Just don't do it too many times in a row because you can permanently damage
the head. Read the instructions.

So we have covered a few reasons why these errors come and go as if by
magic. They are intermittent and recurring. The camera will appear to work
at times, and the next minute it shuts down.

Solution #4 : Fake Solutions
Another reason why the problems come and go is that, as several technicians
have reported, the problem can be a loose connector inside. That is why some
people report that tapping the camera gently or rocking it side to side has
brought it back to life. Some have gone as far as putting cardboard between
the tape door and the tape mechanism in order to exert pressure and keep the
camera working. I can only warn you that these kinds of "repairs" are
temporary and likely to damage the unit further. Control your anger!

Solution #5: Compressed Air
On some models, there is no shield covering the many delicate electronic and
moving parts in the tape mechanism when you open it to replace the tape. A
piece of dirt, grain of sand, or other debris can get caught in the tiny
gears and stop movement or throw them off alignment. You can explore this
possibility by getting a can of compressed air at any computer shop and
blowing it into the inside of the camera. Follow the instructions, keeping
the air nozzle however many inches away from the target as they say.
Practice on some other object first, because if you tilt the can or hold it
too close to the target you can freeze the target and do more damage than
good. This applies to fingers too!

Solution #6: Tape Age, Brand, and Type

Have you tried using a brand new tape? Or only your really old ones? Try a
new tape.

Now for the controversial issue of what brand of tape to use. Controversial
because JVC's own Stacy Sample, Service Coordinator for JVC in Houston, TX
says that "TDK and Maxell tapes tend to be two brands that are very
problematic in our digital line wherein Panasonic, JVC and Fuji seem fine.
We just find that TDK has the most problems, Maxell is a close second and
Sony is 50% of the time. The others I mention rarely have a problem." Why
JVC does not make this information available when you purchase the unit or
visit their many websites is beyond me.

A different point of view I ran into is. Yes, there is an issue, but it has
nothing to do with the brand, but with the tape type. There are MP and ME
tapes. These two types use different particles, and different lubrication.
The two lubricating materials form some sort of goo when mixed together, if
you use both types of tape in the same unit. So as long as you don't mix
tapes of different types, they will work just fine in your camcorder. Some
refer to these types as "dry" and "wet", but I don't know which is which. In
any case, it is not known (to me) how accurate this point of view of not
mixing tape types is.

Solution #7: Do not store tape in unit
Because of the delicate nature of the miniDV mechanism, do not store the
unit with a tape inside. The theory is that a loaded tape will put pressure
on parts of the mechanism and increase the chance that parts will stick
together, making the tape harder to be pulled by the motor, causing the
SAFEGUARD error.