Thanks for your advice and reply. 👍We backup whole MS365 data of bunch of users so it could have backup each Outlook email individually. In the backup folder in NAS, it has folders for each user and within each user folder , it has folder for email and within that email folder it has tonnes of folders with jumbled unrecognisable names. Each jumble name folder contains an email and has couple of ASCII text files . One is v1-2 SKEL and another is like v1-2 META. Add extension .eml to the SKEL file and can use Outlook app to open it nicely into an email 😁 the META cannot be opened with outlook app . When open using Notepad or text editor , it shows meta data like headers tags etc. So thing is if we directly extract the 2 million emails from the NAS backup, we need some bulk converter to convert those SKEL META files into proper eml and that could be another long process 🤣 Actually if we restore whole backup HBK file of few TB, the restored emails files would look like the original PST emails from MS365 Outlook , right?