To disable SPAM filtering for individual mailbox as an end user:

• Login to user's webmail (https://outlook.office.com)
• Settings > Mail > Block or Allow
• Check option: "Don't move email to my Junk Email folder"
• Save changes

Read more: Disable SPAM filtering in Office 365

Ubiquity UniFi Cloud Key controllers are notorious for getting corrupted database after powering them off without clean shut down. Best course of action in such cases is to factory reset the Cloud Key and then restore from a backup up. If no backup is available you'll have to factory reset and reconfigure it from scratch. The main issue with this is that all UniFi WiFi Access Points and other devices that were previously managed by this controller will now be orphaned and appear in devices list as Manager By Other.

 

Read more: Adopt orphaned Ubiquity UniFi devices

I had a task of migrating few thousands contacts and some calendars from Apple iCloud to Microsoft Office 365 (Exchange) system.

Importing Calendars was pretty straight forward:

• Export all calendars in .ics format on a Mac via buit-on Calendar (select your calendar > File > Export > Export).
• Open .ics calendar on Windows Machine with MS Outlook 2016 (which already had Office 365 account setup).
  • Go to View > Change View > List.
  • Drag all relevant appointments into Office 365 account calendar (I skipped appointments older than 12 month).

Read more: Migrating contacts and calendar from iCloud to Office 365

This is how I normally create a company-wide Shared Calendar in Office 365:

• Exchange Admin Center > Recipients > Shared
  • Create a new Shared Account
  • Edit account's properties and in Mailbox Delegation  tab add All Users group to Full Access list.

This will give your users permission to add shared calendar to their MS Outlook and Outlook Web App. If you want the shared account (including Calendar) to be added automatically to users' Outlook, add individual users (rather than All Users group) to Mailbox Delegation > Full Access.

If all of your users are on Windows machines that's pretty much it. Unfortunately things are not so simple if they are on MacOS and iOS. I tried to get help from Office 365 support, but received a not very helpful "we don't support Apple products" or something similar... Luckily after some Googling and bunch of trial and error I finally got it working. Here is what I did:

Read more: Office 365 - Accessing Shared Calendar on MacOS and iOS