Though there are manual steps available to accomplish this task appropriately however, it does not guarantee successful data migration & demands a higher technical expertise. Thus I would like to recommend you an adequate solution named Lotus Notes to Office 365 Migration which helps to get rid of from such problematic issues and successfully migrate from Lotus Notes to Office 365.
If you are looking for the best way to migrate Lotus Notes to Office 365 mailbox, then I would like to suggest you try a free trial version of Shoviv Lotus Notes to office 365 Migration tool. It also helps to export Lotus Notes data into Live Exchange, PST, EML, and MSG.
There are many tools present on the internet with the help you can migrate Lotus Notes to Office 365 but I would like to suggest you proficient tool like Shoviv Lotus Notes to Office 365 tool which works in a hassle-free manner and this tool has the capability to migrate the number of Lotus Notes Mailboxes (.nsf files) into office 365 and Exchange server at once.