I'm reading different things about this. Some say "no" it has to be mailed in. Others say "yes" it can be filed electronically. TaxSlayer Pro, for example, says this: "Amended Returns - Maryland supports electronic filing of amended return forms 502X and 505X." I think TurboTax thinks "no" but not sure who's right. Thanks.
The link I posted is broken because they removed a number that they describe as a phone number but it's not a phone number.
If you're amending your Maryland return in TurboTax, you'll need to print and mail your return or e-file directly with your state.
Please see this TurboTax help article for information.
Yes, it's not Maryland it's the software tax prep companies use. I found a list of products that Maryland approved as of January 2023 and many tax prep products allow e-file of Maryland 502X amended returns, even TurboTax ProConnect can, but not the TurboTax for us civilians.