I work with many data files, I find that the most relieable is tab-delimited. Mainly because it forces the import wizard to open when you import into Excel or Other. From there you can force all fields to the "Text" format.
1. Instead of double clicking to re-open into Excel or other. Open it by going to File/Open. This may bring up the IMport Wizard.
2. Store all numbers as "Text", unless you still have more calculations to do.
3. Might try Export out as Tab-Delimited Text.
Do or Do Not. There is no Try.