Warning at startup of Zcash - latest update

I am getting a warning after starting Zcash. I just updated to the latest Beta tonight.

~/zcash$ Warning: Warning: error reading wallet.dat! All keys read correctly, but transaction data or address book entries might be missing or incorrect.

Can someone let me know if this is serious or a known issue.


When you updated, did you delete the old wallet?

I’m on my phone, so it’s not as easy to find, but I’m sure I read on a post that you had to delete the wallet file when you upgraded, which is not an issue with the test network and test coins.

When you are mining for real, I wouldn’t delete the wallet file.

I did not. Did not see that in any of the instructions, but might have missed it. Even with testnet coins that goes against instinct. I’ll have to check it tonight when I get home. Have it running on an old laptop. I had not mined any coins over night which concerned me. But that may be because difficulty was 500+.
Thanks for suggestion.