Keep in mind that the version of your software is critical when requesting assistance.
The only way to beat this in CR 8.5 or below is to break up the variable into multiple 254 char chunks, or upgrade.
Not being able to see your formula doesn't help either.
You may even be able to break it up on the database itself prior to bringing it in to Crystal, again, since you don't share technical information, one can't advise.
Try posting more than a sentence, such as:
Crystal version
Database/connectivity used
Example data
Expected output
To break it, use LEN() checks against the variable and add to the next stringvar for greater than 254.
Then just drop them all into a text object to display them as one.
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