External Hard Drive switched to NTFS

I have the exact issue. Both my Seagate external hard drives suddenly switched to NTFS and have been used exclusively on macs/macbooks. I have been using these hard drives for 3 years consistently and this has never happened. Are there any fixes without having to reformat my drives? It's such a pain to transfer in and out 1TB worth of files twice.

That likely was the wrong update and reformatted the drive for NTFS. My advice is never use the included software installed on new disk systems like the WDs and/or Seagates. Use Time Machine if you don't know how to backup otherwise use a third-party backup utility such as these:

Suggested Backup Software

1. Carbon Copy Cloner

2. Get Backup

3. Deja Vu

4. SuperDuper!

Others may be found at MacUpdate.

Visit The XLab FAQs and read the FAQ on backup and restore. Also read How to Back Up and Restore Your Files.

How to safely use MacUpdate to download malware-free software:

This site has both free and paid membership accounts. If you have neither then some software will be distributed as an installer wrapper that includes adware/malware you may not want. Such a download may appear on your computer like this: Firefox Installer.dmg. Delete the download and return to the main site where you will find a direct link to the developer's website. Use that link from which to download the software.

To avoid such downloads from MU just create a free membership account. Log into your account prior to using the site. This will avoid the installer wrappers and downloading adware or malware. I continue to use their site without any problems.

If you prefer not to create a membership account then note that on the download page under the price box will be the link to the developer’s site. Use that link and download the software directly from the developer circumventing the use of MU altogether.

You will find warnings from one user in this topic warning that the site is “dangerous.” His warning is an exaggeration and it is false. Learn the facts. You merely need to establish a free or paid membership to avoid problems with malware. Don’t pay attention to other users who warn you away with hyperbole and rhetorical insults.

Here is what I know about Seagate drive.

• Seagate's external Drive for Mac comes in NTFS format. ( It did not switch. It is in NTFS from beginning )
• There are two bundled software, utility and driver. ( jChey, which did you updated, utility or driver? )
• The driver is a modified version of PARAGON's driver ( noted by lllaass ). which makes NTFS writable.
• Seagate's driver can be downloaded free from seagate site, but it works only on Seagate drives.
• Seagate's driver is a bit older than PARAGON's (14.0.x compared to 14.1.x) as of today.

Then today I found an interesting article on PARAGON site.

http://kb_wp.paragon-software.com/article/727

"As you already know with EL Capitan OS release, Paragon introduced new version of NTFS for Mac with full El Capitan support.

However, this new NTFS for Mac 14 version differs in usage compared to previous versions of Paragon file system driver because in El Capitan apple changed their Disk Utility in a way that NTFS for Mac cannot fuse with it and you cannot see Volumes, mounted with third party drivers in new Disk Utility. ..."

Okay I just remembered that it probably was NTFS all along and that the Seagate software (Paragon) that helped me read the harddrive was due for an update. All's well now.

Disks do not reformate themselves. Also formatting erases the disk.

I bet it started after you updated to El Capitan and that the disk is formatted in NTFS format (a PC format).

A Mac can't natively write to a NTFS formatted drive but there are apps like

Tuxera NTFS for Mac

Paragon NTFS for Mac® 14

External HDs come formatted NTFS and some may come with an app that apps writing to NTFS formatted drives. You have to update the app to be compatible with El Capitan.

Some HDs come with one of the above apps to allow writing to a NTFS drive and El Capitan requires an updated app

Use Disk Utility to first change the format to MSDOS/FAT32. Then re-partition the drive changing the partition scheme to GUID from MBR, and use a Format type of Mac OS Extended, Journaled with which to Erase the drive after you partition it. All data on the drive will be lost.

Note that drive formats do not change without user action. However, new drives may come to you pre-formatted for NTFS. If the drive had never been correctly prepared when you got it, then became corrupted severely it may revert to the underlying format, but frankly, I've not seen that ever happen.

You are using El Capitan. Open Disk Utility. Locate the out-dented disk entry in the Disk Utility sidebar and select it. Now click on the Erase icon in the toolbar. The rest should be fairly obvious. Two dropdown menus appear from which to select the GUID partitions scheme while the other is for the Format type - Mac OS Extended, Journaled. Name the volume if you wish and click on the Erase button.

No. I do not know how such a thing would happen. i have never seen a formatted drive switch on its own to a non-native format.