Disk Writer Error Message "Failed to Write MBR (5) (1)"

bleedingkanzas · Post by **bleedingkanzas** » Sat Apr 18, 2026 6:41 pm

Hi everyone,
I'm new to use the DCP-o-matic software. I'm a manager of a small theater and I'm trying to make a DCP version of trailer for an upcoming special screening we're doing. I tried to use the Disk Writer software to make sure the external hard drive I'm using will be correctly formatted and such to read the files. I just tried using it and it gave me this error message "Failed to Write MBR (5) (1)". I'm curious if anyone else has encountered this and what I can do to fix this.

Thanks in advance for your assistance!

Post by **carl** » Sat Apr 18, 2026 6:43 pm

Hi, this is a known bug where DCP-o-matic doesn't manage to get the right macOS permissions. Please can you try this workaround:

https://dcpomatic.com/faq/27

Let us know if that doesn't fix it.

bleedingkanzas · Post by **bleedingkanzas** » Sat Apr 18, 2026 8:39 pm

Those instructions did fix the initial issue. However, I then ended up getting this error message after I got the program to process the DCP file I was working on: "boost::filesystem::directory_iterator::construct: No such file or directory [system: 2]"
I tried restarting the program and realized that my laptop was no longer recognizing the external hard drive I was using and I had to wipe the drive and lost my progress. Thankfully I didn't have anything else on there since I just got it yesterday for this purpose. But yeah, I'm curious where I went wrong and how I can fix/avoid it going forward.

Post by **carl** » Sat Apr 18, 2026 8:47 pm

So this is the external drive that you are copying the DCP onto? You know that the DCP-o-matic Disk Writer will wipe the drive that you ask it to use?

bleedingkanzas · Post by **bleedingkanzas** » Sat Apr 18, 2026 10:50 pm

Yeah, I was aware of that. But, I had to go back and wipe the external hard drive again because my laptop was no longer recognizing the external hard drive after I got that other error message on Disk Writer.

Post by **carl** » Sun Apr 19, 2026 10:24 am

Do you mean macOS was not recognising it, or the disk writer was not recognising it?

Does this ""boost::filesystem::directory_iterator::construct: No such file or directory [system: 2]" happen every time you try to write the DCP?

IoannisSyrogiannis · Post by **IoannisSyrogiannis** » Sun Apr 19, 2026 10:30 am

bleedingkanzas wrote: Sat Apr 18, 2026 8:39 pm [...]
I tried restarting the program and realized that my laptop was no longer recognizing the external hard drive I was using [...]

I might be barking under the wrong tree, here. Yet, please let me understand, was your computer expected to recognize the MBR, EXT2/3 drive and partition?

(O.K. I see I was writing simultaneously with Carl, here.)

DCP-o-matic

Disk Writer Error Message "Failed to Write MBR (5) (1)"

Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"

Re: Disk Writer Error Message "Failed to Write MBR (5) (1)"