You are constantly getting a message Mac 1 hfs volume repair required on your Mac system and you are also not able to access the contents of that particular volume. You car facing that problem because the volume has gone corrupted which can occur if the partition process has gone wrong, the header of file system is damaged, the drive is infected by virus or any thing else. The only way to fix mac 1 hfs volume repair required problem is to scan it with the disk utility which will find the cause and try to remove it. If it is not successful then you have to format the drive with disk utility only. After the formatting you will getting the message anymore but the stored data will be lost. Now to recover them the time machine can prove helpful. However on some occasions the time machine fails to provide the backup. So you have to use the Mac data recovery software which can scan and recover the files which were lost from that volume. The software has an advance scanning mechanism which can find even long lost data and files in the preview. so you must download and use the software and resolve mac 1 hfs volume repair required issue.