Bootcamp partition missing after update to Catalina

In your GPT entry, there is no PartitionType GUID. Also, the start/size/end of a damaged file system is tricky to use.

Can you post the output of

sudo dd if=/dev/rdisk0s3 count=5 2>/dev/null | hexdump -C

We should look at the dump to see what is in the first few blocks.

If you are already running Testdisk, you do not need to exit. We need to run a Quick Search and check if there are any MS Data entries that we can look at.

If you position the selection on the EFI partition, do you see a Deeper Search option?

If you mount disk0s1, do you see a Microsoft directory under the EFI tree?

Did you check if there was a NTFS header after you added GPT3? There can be alignment gaps, so Testdisk start/size/end should be used to recreate GPT3. Does Testdisk show a valid NTFS file system?

Bitlocker will disallow any access, so headers cannot be verified. Can the volume be decrypted and BitLocker removed?

Do not modify anything using Testdisk, because it does not understand the structures on disk when Mac and Windows are on the same disk.

We need to look at the NTFS partition and use the 'p' command to look at the directory.

gingerkiwi wrote:

Not in the output of the analyse disk quick search, is there another testdisk function I should run to check?

There is a Deeper Search option, if you want to use it, but it can be very slow.

Run a Quick Search. Once it completes, you should have an option to run Deeper Search.

If you quit this page, do you get back to the list?

Try

sudo diskutil mount /dev/disk0s1