Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
:confused: My guess would be the output on your SM58 is higher than that of "normal" PC mics... closer to what the line-level input on your MBP is expecting.
I haven't tried an XLR->1/8" adapter with my Sennheiser HMD280 Pro mic yet but I've never had luck with any other headsets or normal PC...
All current Macs lack a mic preamp, they only have line-level inputs.
So, you'll either need a mic preamp (Griffin iMic would work, it's USB), or a USB mic. The Blue snowflake would be an excellent USB mic choice, but is probably over budget.
Open your c:\windows\system32\drivers\etc\hosts file in notepad and delete anything directing myspace to google's IP address. Sounds like someone is having some fun with you.