The following is the IRS criteria for the filing of the Federal Tax Lien
When there is an Unpaid Balance of Assessment  below $5,000 and filing the lien will promote payment compliance. IRS will file a NFTL. This gives IRS the right to file a federal tax lien at any time. IRS can justify anything they want, sad.
This will also apply to additional assessments on currently open cases and those being reported as currently not collect-able. IRS will  take into account if assets are owned or the possibility of future assets being acquired during the collection statute period. In the case of accrual only liens, consider the amount of the accruals.
If there is a UBA of any amount for an entity and the entity is not adhering to compliance requirements such as federal tax deposits, return filings, the IRS will file a NFTL.
The aggregate UBA is $5,000 or more file a NFTL
IRS will determine the need to file a NFTL when there are additional assessments.
An installment agreement does not meet streamlined, guaranteed, or in-business trust fund express criteria file a NFTL.

If an installment agreement meets streamlined or in-business trust fund express criteria, then a lien may be filed.
An open account with an aggregate UBA of $5,000 or more is being reported as currently not collectible file a NFTL.
A case involving both assessed and unassessed periods will be reported currently not collectible the NFTL filing may be held up to include both period types on the NFTL.
A good tax professional can find ways not to have the tax lien filed. Call Fresh Start Tax 1-866-700-1040