Set Default Sharing to "People with Existing Access"

Hi LisaJo48 ,

My previous comment was pointing you to creating your own code that did 2 things:

- get a list of all the sites in your tenant

- then for each one of those set the following 

Something like the following| NOTE check this with ONE or two sites first, before doing it across all 800 of your sites.

 Import-Module Microsoft.Online.Sharepoint.PowerShell -DisableNameChecking

#change XXXX for your tenant name     
 $AdminSiteURL="https://xxxx-admin.sharepoint.com"
     
 $Credential = Get-credential
Connect-PnPOnline -Url $AdminSiteURL -Interactive
     
 #sharepoint online list all site collections powershell
#Get All Group Sites
 $SitesInTenant = Get-PnPTenantSite -Template GROUP#0

#for each site then set the property you want
 ForEach($Site in $SitesInTenant)
 {

#reference https://pnp.github.io/powershell/cmdlets/Set-PnPSite.html#-defaultlinktoexistingaccess

Set-PNPsite -identity $site.url -DefaultLinkToExistingAccess $true

}

NOTE - set-pnpsite code updated 24 Nov to be $site.url

Reference for this is here

https://pnp.github.io/powershell/cmdlets/Set-PnPSite.html#-defaultlinktoexistingaccess