It would most likely not be a problem; if it has been 10 years or more since the completion of a Driving Under the Influence sentence, a person could be deemed rehabilitated simply as a result of the passage of time. This path would also allow them to stay in Canada. This solution is only possible in cases where someone has a single, non-serious conviction on their record. If you have more than one conviction, you must apply for criminal rehabilitation to clear your criminal record to enter Canada without any issue.
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How can old convictions impact a foreign investor's chances at immigration in Canada?
I'm an investor from a non-EU country looking to immigrate via investment to Canada with my family. During my college days, I had a driving under the influence conviction and fine, which I have paid off many years back. Would this ruin my immigration chances?