Tasked by congressional investigators with uncovering all the emails related to the alleged targeting of conservative political groups with undue scrutiny, the Internal Revenue Service made some new emails available to investigators on Friday. However, in a statement, the agency confessed that former IRS executive Lois Lerner’s computer crashed in 2011 and efforts to restore some of the data lost in that crash have been unsuccessful.

The IRS informed congressional investigators on Friday that they have been working to uncover all of Lerner’s emails, even those not relating to ongoing investigations. While searching for those emails, however, they encountered a problem:

Via the Wall Street Journal:

In the course of collecting and producing Ms. Lerner’s additional emails, the IRS determined her hard drive crashed in 2011. At the time, Ms. Lerner asked IRS IT professionals to restore her hard drive, but they were unable to do so. Nonetheless, the IRS has or will produce 24,000 Lerner emails from this 2009-2011 time period, largely from the files of the other 82 individuals

“The IRS said it has done its best to reconstruct the emails of the former executive, Lois Lerner, who retired as the controversy unfolded last year,” The Wall Street Journal reported on Friday.

The IRS statement asserts that the agency has made “unprecedented efforts” to work with investigators and provide them with all the materials they have requested.