[Someone1234]

The unfortunate answer is "it depends."

There's three reasons why text might appear blocked out: corrupt data (we'll ignore this), data in formats the text renderer doesn't "understand," and data in formats it DOES understand but doesn't have the prerequisite fonts to draw.

Typically when it is a lack-of-fonts issue you can copy it back out and paste it elsewhere and it will work fine as the data's consistency is kept.

But when the text renderer literally doesn't understand the underlying data (either because it is misconfigured or doesn't fully support UNICODE), when you try to copy back out you'll often get a corrupted version of the underlying data which cannot be reused (e.g. a 2 byte character treated as two 1 byte characters).

That issue is less and less common in 2014, as MOST text renderers support 2 byte UNICODE characters even if they won't have the fonts to render the full sets. But around the year 2000, it was fairly common to run across a text editor which under-the-hood was just ASCII and it would corrupt irrecoverably UNICODE inputed.