I'm using InDesign CS3. I often copy text boxes between different documents.
I'm not using any character styles in any of these documents.
Why is text that is aligned left in one file becoming justified when copied to another file?
What's about Pragraph Styles?
This is usually the result of using the same style name in two documents. Say you have a style called “Body Copy” using Helvetica in document 1 and the same style name using Futura in document 2. If you copy some text that uses “Body Copy” from document 1 to document 2 anything that is Helvetica will change to Futura.
You might be using different versions of the [Basic Paragraph] style, which is predefined in all InDesign files and cannot be deleted. Worse: by default all text is formatted using this style and all new styles created are based on it. This is a common trap for new and even experienced users. The inclusion of the style was a big mistake on Adobe’s part, but after three (or is it four?) versions without correcting it it looks like they are blind to the error.
The solution to the [Basic Paragraph] problem is to never, ever, use it as a style. Make sure any text that is not using styles uses [No Paragraph Style] as a paragraph style, not Basic Paragraph. If you are using styles (and shame on you if you aren’t) then set your styles to be based on [No Paragraph Style] or on other styles you define, but never based on [Basic Paragraph].