The time required to import MBOX to Hotmail mainly depends on the size of the MBOX file, the number of emails, and the size of attachments. A small mailbox with a few hundred emails can be imported within minutes, while large MBOX files containing thousands of emails may take longer. Using a structured migration method, such as the MailConverterTools MBOX Converter Tool, helps complete the process smoothly while keeping emails and attachments intact.