An arbitrary value, or the letter "E" will appear in the display if the calipers have not had the origin set. See instructions above.
"ErrC" is displayed and the display is flickering when the scale surface is contaminated. That means it's dirty or wet with water. Clean the scale, dry it and apply a small amount of thin oil (low viscosity) in order to repel any future water contamination.
"E" at the end of the reading, such as 2.501E, means you've moved the slider too quickly. However, the reading is still correct. (So why do they tell you this?) Slow down a little, next time. It can't hurt.
"E" if caliper is stationary. Same as ErrC.
For more tips on care, calibration and usage of the Mitutoyo Digimatic caliper refer to our general discussion of calipers on page 11.