In this decision from the Third Appellate District of California, the Court found that Holmes’ emails did not fall under the protection of attorney-client privilege (warning – link opens a 40-page PDF of the ruling).
Because she wrote them on a company computer with the knowledge that the company had a “we own the data” policy.
YMMV (that’s my cute way of telling you, other state laws are contra, e.g. New Jersey’s Stengart). From that post:
“I suppose if I simply admonish you not to use your company collateral for personal purposes, you’re going to ignore me, but it’s missing the point, anyway. You can’t un-ring the bell. Sure, I understand that, in this case, they were forced to return the emails and there was to be a decision as to whether the law firm that read the emails could even continue in their representation, but the bottom line is, the emails were still read.”
A little fun fact? Holmes never said, “Elementary, My Dear Watson”.