Recover deleted permissions in SharePoint 2016/ 365

[BigHomieBear2013]

I accidentally removed permissions and grouped permissions.  I am looking for a way to recover them outside of performing a restore.  Can someone please assist?

[#2]

@BigHomieBear2013 : could you please provide some details of this accidental removal of permissions. Was this activity performed on a specific site collection or subsite? And was this performed on SP 2016 or SPO (Office/Microsoft 365)?

[#3]

@Surya_Pammi  thank you for responding.  It was at the subsite level in SP 2016

[#4]

@BigHomieBear2013 : Here we need to consider two things. Firstly SharePoint Groups creation. You will be able to only restore the default SharePoint groups like Owners, Members & Visitors. If any other groups are missing you need to manual create them with appropriate permissions. Go to <site URL>/_layouts/15/groups.aspx and restore default groups. Then try inheriting permissions from root site or site collection as per your requirement. But this will have huge risk of loosing permissions.

Best possible way is to restore site back (if you have a backup) in lower environment (DEV/UAT) and check for the groups & permissions. Using PowerShell or manually you can map the groups & users accordingly.

[#5]

Thank you!