SQL Server 2012 :: Update Statement Will Not Update Data Beyond 7 Million Plus Rows Out Of 38 Millions Rows

I run the following statement and it will not update beyond 7 million plus rows and I have about 38 million to complete. I keep checking updated row counts and after 1/2 day it's still the same so I know something is wrong because it was rolling through no problem when I initiated it. I need to complete ASAP so it's adding to my frustration. The 'Acct_Num_CH' field is an encrypted field (fyi).

SET rowcount 10000
UPDATE [dbo].[CC_Info_T]
SET [Acct_Num_CH] = 'ayIWt6C8sgimC6t61EJ9d8BB3+bfIZ8v'
WHERE [Acct_Num_CH] IS NOT NULL
WHILE @@ROWCOUNT > 0
BEGIN
SET rowcount 10000
UPDATE [dbo].[CC_Info_T]
SET [Acct_Num_CH] = 'ayIWt6C8sgimC6t61EJ9d8BB3+bfIZ8v'
WHERE [Acct_Num_CH] IS NOT NULL
END
SET rowcount 0