It is quite unfortunate when Mac boot drive error appears all of a sudden. Let's have an example wherein while your Mac gets stuck on the Apple Logo showing spinning wheel aside. In consequence of that your Mac does not respond and failed to boot completely. This type of incident can be occurred in some point while accessing your system. Even though Mac boot drive error could come across due to several unpredictable reasons, however the major probable cause is due to faulty hard drive cable or logic board etc. so with proper foresight or good sense you can overcome from such difficult situation. Now coming into resolving this issue and as there might be faulty cable would be liable for the emergence of this issue that's why removing the cable would be fruitful in resolving Mac boot drive error. But if the issue does not remove then reformatting hard drive is the mere choice. In case of data loss one should go with efficient data recovery either-way. First one is through backup and going with Mac Data Recovery Software is the ultimate and reliable option in lack of backup. Hopefully now you can fix Mac boot drive error without hassle!!