Q: Drag and Drop Files Onto Seagate External Hardrive

What is the drive formatted as? this is extremely likely the issue.

FORMAT TYPES

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X.
• Maximum file size: 4GB.
• Maximum volume size: 2TB
• You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB.

NTFS (Windows NT File System)

• Read/Write NTFS from native Windows.
• Read only NTFS from native Mac OS X
• To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
  • For Mac OS X 10.4 or later (32 or 64-bit), install Paragon (approx $20) (Best Choice for Lion)
  • Native NTFS support can be enabled in Snow Leopard and Lion, but is not advisable, due to instability.
• AirPort Extreme (802.11n) and Time Capsule do not support NTFS
• Maximum file size: 16 TB
• Maximum volume size: 256TB
• You can use this format if you routinely share a drive with multiple Windows systems.

HFS+ ((((MAC FORMAT)))) (Hierarchical File System, a.k.a. Mac OS Extended (Journaled) Don't use case-sensitive)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner or SuperDuper! backups of Mac internal hard drive.
• To Read HFS+ (but not Write) from Windows, Install HFSExplorer
• Maximum file size: 8EiB
• Maximum volume size: 8EiB
• You can use this format if you only use the drive with Mac OS X, or use it for backups of your Mac OS X internal drive, or if you only share it with one Windows PC (with MacDrive installed on the PC)

EXFAT (FAT64)

• Supported in Mac OS X only in 10.6.5 or later.
• Not all Windows versions support exFAT. 
• exFAT (Extended File Allocation Table)
• AirPort Extreme (802.11n) and Time Capsule do not support exFAT
• Maximum file size: 16 EiB
• Maximum volume size: 64 ZiB
• You can use this format if it is supported by all computers with which you intend to share the drive.  See "disadvantages" for details.

DaxxMojoux

I just want a simple drag and drop so I can free up some space on my computer.

Understood, ... go into FINDER at top then PREFERENCES  then GENERAL tab

then check "hard disks" and "external disks"

THIS WILL PUT A HD ICON ON YOUR DESKTOP YOU CAN OPEN AND DRAG AND DROP FILES TO

THEN  verify the format of your external HD

go to DISK UTILITY and verify what it says your HD is formatted as under the "ERASE" tab

HFS+ above is the "mac format" however do NOT erase / format the HD, since this will erase it.....UNLESS you want to do this

Format (erase) it in "mac osx Extended journaled"

AFTER THIS YOU CAN DRAG AND DROP FILES AS YOU LIKE 

I'm confused here, if you don't understand what that says, how does it solve the problem?

Is your problem actually solved?

From inference by the OP comment below:

"But Seagate just seems to just seems to say xxx you, we're gonna do it backwards"

it would be presumed the format is incorrect on the external Seagate

OR (as per the second comment) that the OP does not know the location for opening up the external HD for "dragging files to"  as he wishes.

Hence the second post with step by step simplicity

DaxxMojoux 

   I got the first part, but how do I verify the format of my external harddrive

Applications > utilities > disk utility

go to DISK UTILITY and verify what it says your HD is formatted as under the "ERASE" tab

see from mine below, HD on left selected,   .......ERASE tab highlighted.... and middle right roughly, it says "MAC OSX EXTENDED JOURNALED"

thats the format,  but yours may be different of course

bottom right ERASE tab lets you erase/ FORMAT your external as you like (remember this erases all data ON THE HD!)

highlighted in RED   Erase.......format (middle) ...........erase ACTION to Erase/Format (bottom)

You are the only one that can push the solved button, it does not happen otherwise. No matter, you need to verify the format of the drive, and (if the format is MSDOS) the file size.

Follow Veritas's instructions as to finding the format, post back with the answer.

Please answer the question, what is the current format if the drive, simple and descriptive answer please.

That says the drive is MSDOS and NTFS, which is not possible so please post a screenshot and  I will read it for myself.