Rookie needs help

I have a usb drive attached with some excel files. I open a file and make changes in Numbers. I try and save it as an excel file back to the same location and I get a series of messages as follows.

"the file already exist. do you want to replace it" to which I answer "Replace". 
"
Numbers cannot remove the old document. Would you like to make the old document into a backup file and then save your document?"

"An existing file can’t be removed because you may not have permission to write to the file or folder."

I select save and see this

"Numbers cannot create a backup file. Would you like to save the current version of your file anyway?"

"A backup file can’t be created because you may not have permission to write to the file or folder, or there is not enough space on the disk."

I select save and see this

"The document “CIS265 Chapter 1-4 Qizzes.numbers” could not be exported as “CIS265 Chapter 1-4 Qizzes.xls”. "

"The file “/Volumes/New Volume/CIS265 Winter 2011/Quizzes and Tests/CIS265 Chapter 1-4 Qizzes.xls” couldn’t be found."


Can someone tell me what my problem is

What is the format of the USB attached drive ..... NTFS, FAT32, HFS+, .....


Cheers ... McBie

I am sure it is ntfs. how can i tell for sure

it is ntfs

Then you can't write anything to the drive without a 3rd party tool ...

Have a look here PARAGON Software Group - NTFS for Mac, communication channel between Mac OS X and Windows

There are other tools out there to allow you to write to NTFS drives and there are multiple posts on the forum here that address other possibilities. Have a look around ...

Cheers ... McBie

Thank you man

While you're at it, you could reformat the USB drive to FAT32, then you can easily switch and move around Mac and Windows. Reformatting, of course, wipes your drive.

Thanks Yogi. I did this and it solved the problem. The drive I formatted is a sata drive 7200 speed. Will the fat file system slow it down?

FAT32 is less efficient under Windows than NTFS. It is also less efficient than HFS+ on Mac OS X.

Which means that it is just marginally slower than each OSes propietary systems, and may not yield as much usable Disk space either.

But it is interoperable, which is a big advantage. Depending on your use, you won't notice any difference.

Please keep in mind that the FAT32 file system has a limitation on the file size of each individual file ..... Max. File size is 4GB per file.

Cheers ... McBie