Revision #1

Introduction

It sounds strange and it's kind of controversial way of supporting the FIM product, but uninstalling FIM properly is part of the FIM administrators job too.
There might be various reasons to remove the product from your environtment.
- after a merger, the product is migrated to another FIM installation on another network
- only particular and limited functionality is used (and more specifically served by another product)
- functionality is phased out, installed functions are not used anymore
- (feel free to add more scenarios in here)

Whatever the reason, you should do it properly and thoroughly.
What are the things you should think about?
It's not as simple as reversing the installation procedure.

Backup

Inventory

• Servers
•  Databases
  •  FIM Service
  • FIM Sync
  • SharePoint
• FIM security groups
  •  FIM Sync Admins
  • FIM SYnc Browse
  • FIM Sync Joiners
  • FIM Sync Operators
  • FIM Sync Password set
• Service Accounts 
  • FIM Service
  • FIM Sync
  • FIM portal (sharepoint/IIS)
  • FIM MA account
  • Management agent accounts
• Client SW  
• AD security
  • Service Account Rights & Permissions on OUs
  • Replicating directory changes rights
  • SPN settings
  • Service Settings

Removing components

Uninstalling FIM Portal
Uninstall FIM Service
Uninstall FIM Sync
Removing DB
Uninstall SQL 
Uninstall PCNS
Uninstall SharePoint Foundation

Remove FIM SPN configuration

setspn -l servi

Remove service account rights from AD

Remove service accounts

Hints & tips

Source references

Uninstalling Forefront Identity Manager 2010 R2
http://technet.microsoft.com/en-us/library/jj200258(v=ws.10).aspx

See also