I have Microsoft Dynamics CRM 2015 and the database file (.mdf) is around 20 Gb and the Log file (.ldf) is about 550 Gb. I tried shrinking ldf file as discussed in this link
However, after the database log file was shrink, CRM stopped working. Can anyone advise.
CRM stopped working
What error messages do your receive?
Just based on my assumptions:
Obviously that database is not in a SIMPLE recovery mode and no scheduled backup of the transaction log configured.
SELECT name, log_reuse_wait_desc, recovery_model_desc FROM sys.databases WHERE name = 'yourDB'
ALTER DATABASE [yourDB] SET RECOVERY SIMPLE
OR, fix your backup of transaction log if, this is a reason
USE [yourDB] DBCC SHRINKFILE (2, 256)
When your database back to the operational state you have to decide what kind of backup scheme do you want yo have:
Depends on a choice, you will have to stay with SIMPLE recovery or switch back to FULL, but add missing scheduled backups of your transaction log