Bootcamp partition with Windows 7 no longer recognisable

Type 'N' and continue. Can you post the Terminal session for both the sections? We can then see if there are any other errors.

Yes.

Excellent!

Can you see Windows files in macOS Finder? macOS Catalina will support W7, if the installation of W7 preceded the upgrade to Catalina. Catalina does not support a new installation of W7. Only W10 new installations are supported.

This is not a valid NTFS header. Take a look at El Capitan has deleted my bootcamp window… - Apple Community . There is a tool called Testdisk, which can find a lost NTFS header. The discussion also is a good tutorial. If you can follow it, we can try and correct the issue.

Your first MS Data entry at start 101003264 (size 875767808) does not match MBR 4 at start 102066928 (size 874444056).

The Testdisk entry at 101003264 seems to be the correct one. We should check and verify the output of 'p' command for this entry.

Rebuild GPT4 using start/end offsets

1. Sudo gdisk /dev/rdisk0
2. P (print the full list of parts)
3. D (delete)
4. 3 (GPT3 - this overlaps with the NTFS Start)
5. D (delete)
6. 4 (part 4)
7. N (new part)
8. 3 (part 3 - since we have deleted GPT 3 and GPT 4)
9. 101003264 ( - Start offset in sectors or the start point for Bootcamp part)
10. +875767808 ( - Size offset, as opposed to End offset)
11. 0700 (Windows part type)
12. P (print list of all parts just to see what changes will be made)
13. W (Write the new GPT)
14. Y (Yes! really write the new GPT)

Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see thesample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.

1. Sudo gdisk /dev/rdisk0
2. P (Print list of parts)
3. R (Recover)
4. O (print current Hybrid MBR)
5. H (chooses Hybrid)
6. Partitions numbers to be hybridized: 2 3 (since we are deleting GPT 3 and GPT 4 in the previous section)
7. Y (Good for GRUB question)
8. N (part 2 boot flag)
9. Y (part 3 boot flag make NTFS bootable partition)
10. O (print current Hybrid MBR)
11. W (Write the new MBR)
12. Y (Yes! write the new MBR)
13. Reboot

gradiusV wrote:

I have been thinking about installing Windows 10 this time, since it has actual support and updated drivers. If I were to install W10 would it be advisable to upgrade my macOS to Mojave or Catalina? If I install it with my current macOS High Sierra and I update it to either of these systems, could it mess up with my Windows partition again?

I recommend Mojave before you install W10.

And just in case; if I stick to Windows 7 anyway, I can only install it with High Sierra, correct? And since it's been said that new macOS carry on old W7 installations, what precautions should I take so it wouldn't mess up with my partition again?

You can remove the current installation, re-install W7, create a Windows backup on an external disk, and then upgrade to Mojave. You may also want to consider Winclone, which will let you restore W7. Be aware that Microsoft is pushing Windows users to W10 (https://support.microsoft.com/en-us/help/4057281/windows-7-support-ended-on-january-14-2020).

If you have existing screen shots, there is no need to run it again. If you can post them here, we can take a look.

• You will also need to delete GPT 3, because it overlaps the Windows partition.
• Instead of '2 3 4', you will need to use '2 3'.

• Are you currently on High Sierra or Catalina (or Mojave)?
• Can you post the output of
  • diskutil list
  • diskutil repairDisk disk0