Bootcamp partition disappeared after El Capitan Upgrade

I upgraded to El Capitan from Yosemite through the App Store. When I press the Option key on boot-up, my Bootcamp partition with Windows 10 and the recovery partition are no longer visible. I really need to recover the Windows partition. I've found a few other threads with the same issue, but I'm creating a separate one since otherwise things might get confusing. I really don't want to mess anything up and lose the data on my Windows partition.

$ diskutil list /dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.3 GB disk0 1: EFI EFI 209.7 MB disk0s1 2: Apple_CoreStorage Macintosh HD 275.1 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 4: Microsoft Basic Data 160.4 GB disk0s4 /dev/disk1 (internal, virtual): #: TYPE NAME SIZE IDENTIFIER 0: Apple_HFS Macintosh HD +274.8 GB disk1 Logical Volume on disk0s2 AB8CA084-4793-49EA-968B-F2CDA8D21AC1 Unencrypted

$ diskutil cs list CoreStorage logical volume groups (1 found) | +-- Logical Volume Group A1BF0291-2C38-426A-BC76-AAC4D302E7C7 ========================================================= Name: Macintosh HD Status: Online Size: 275129389056 B (275.1 GB) Free Space: 18960384 B (19.0 MB) | +-< Physical Volume DF3AFE15-2E63-4A56-9263-273EB952CDEE | ---------------------------------------------------- | Index: 0 | Disk: disk0s2 | Status: Online | Size: 275129389056 B (275.1 GB) | +-> Logical Volume Family C0ACF044-B915-4024-AB1E-67EDD8725683 ---------------------------------------------------------- Encryption Type: None | +-> Logical Volume AB8CA084-4793-49EA-968B-F2CDA8D21AC1 --------------------------------------------------- Disk: disk1 Status: Online Size (Total): 274758107136 B (274.8 GB) Revertible: Yes (no decryption required) LV Name: Macintosh HD Volume Name: Macintosh HD Content Hint: Apple_HFS

$ sudo gpt -vv -r show /dev/disk0 Password: gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060 gpt show: /dev/disk0: Suspicious MBR at sector 0 gpt show: /dev/disk0: Pri GPT at sector 1 gpt show: /dev/disk0: Sec GPT at sector 977105059 start size index contents 0 1 MBR 1 1 Pri GPT header 2 32 Pri GPT table 34 6 40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B 409640 537362088 2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC 537771728 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC 539041264 124748304 663789568 313315328 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 977104896 131 977105027 32 Sec GPT table 977105059 1 Sec GPT header

$ sudo fdisk /dev/disk0 Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors] Signature: 0xAA55 Starting Ending #: id cyl hd sec - cyl hd sec [ start - size] ------------------------------------------------------------------------ 1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] 2: AC 1023 254 63 - 1023 254 63 [ 409640 - 537362088] 3: AB 1023 254 63 - 1023 254 63 [ 537771728 - 1269536] Darwin Boot 4: 0C 1023 254 63 - 1023 254 63 [ 663789568 - 313315328] Win95 FAT32L