My house was built in 2007 and I couldn't recall a nonpayment for the AC was sent to me. Now a title search shows a mechanical lien was filed in 2007 and it has not been renewed.
If a contractor files a M&M lien but does not file suit to foreclose the lien within 1 year of recording, the lien is unenforceable. You will need to hire an attorney to file a suit to expunge the lien. This is called a Summary Motion to Remove a Lien pursuant to Texas Property Code §53.160.
The lien is invalid if a lawsuit to enforce it was not filed within one year after it was filed. You may have to file suit to remove it, but some title companies and lenders will ignore it if no suit was filed to remove it. Talk to them.
I am a lawyer but I am not your lawyer. The information in this email is general information but is not specific advice about your specific situation.