You have tried all things to fix 'invalid b-tree node' error on your Mac but none of them works and also you are unable to access the data stored in the Mac drive. The Mac OS X uses the hfs + partition on the Mac drive and the every file in the drive is stored in hierarchy known as b-tree. If it is distorted then the drive will get corrupted and you won't be able to access the stored files. You have to fix invalid b tree node error and that you can do by using the inbuilt disk utility. It will scan the drive for any inconsistency and then try to fix it. If the drive is not fix then you have to format the drive to fix 'invalid b-tree node' error. It will create a new node tree and all the files will be erased. You can then restore the files by using the time machine utility or if it does not work you can try Mac data recovery software. It scans the Mac drive and provide the list of files in the preview. You can then choose the files you want and they will be restore back in the Mac drive. so now it is easy to fix invalid b tree node error and get back all the lost data.