The possible reasons why your accountant's copy is grayed out because you did not remove the accountant's copy restriction. To remove restrictions, you can follow the steps below:
Go to the File menu,
Select Accountant's copy, then Client Activities.
Click Remove Restrictions.
A prompt message will appear. Read it and make sure you want to remove the Accountant's Copy.
Select Yes, I want to remove the Accountant's Copy restrictions, then OK.
Once you've done, either resubmit the accountant's copy or manually make the changes like what your accountant did to your accountant's copy.
I'll add these articles for additional information about the process:
I am the accountant, and cannot return the changes copy to the client, but your steps will make it possible for the client to remove the Accountant's copy so they can keep working while I figure it out!
Same problem here (2018 Premiere Accountants Edition). I was on the telephone with support for an hour yesterday. That was a huge waste of time. If I understood the lady correctly, she was referring me to technical (whatever that is), and they would give me a call back. Never happened! I wish Intuit would step up its game for those of us who have clients still using desktop.
Your QBD 2018 Accountant is outdated and I am not sure Support will entertain you. Do you run your QBD 2018 on Win 8.1 or 10? It is highly possible your Windows OS was updating something recently and it doesn't work with QBD 2018. Consider to reinstall your QBD 2018 in compatibility mode Win 7.
If you still have clients using QBD 2018, you may consider purchasing a QBD Accountant 2019 on a one-time license as another option.
Thanks for taking the time to follow along with the thread and sharing your concerns here in the QuickBooks Community.
Before we get started, I wanted to ask a couple of questions to clarify a couple of things. Are you sending the file using your personal email or are you using the Accountant File Transfer Service? If sending by email, how large is the file? Has your client checked their junk/spam folder?
While I await your response, I wanted to share a couple of help articles about importing accountant changes, should you need it in the future.