External HD/Time Machine Errors

Question

When restarting my iMac I got a string of errors telling me that my back-up volume needed to be repaired. My iMac wouldn't recognize the external HD and the error message said the external was 'read only'. The external HD didn't show in 'Disk Utilities'. I unplugged and restarted the iMac and still have the error icon in the upper task bar. I've tried to repair permissions and repair the disk but I keep getting the error, 'disk is read only'. Should I reformat and try to restore Time Machine back-ups or take it to the shop. The iMac is now showing the external drive one my desktop and I can view old back-ups but if I try to do a back-up, it keeps telling me my external drive is 'read only'.

Answer 1

This is the report from Disk Utility when I run 'Verify Disk'. I'm unable to run 'Verify Disk Permissions' or 'Repair Disk Permissions'.
Verifying volume “Iomega HDD”
Checking Journaled HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Incorrect block count for file 0000000001f3dc7e
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f42845
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f489d3
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f4a029
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f4f34b
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f5453d
(It should be 1 instead of 0)
Incorrect block count for file 0000000001f552a3(It should be 1 instead of 0)
Incorrect block count for file 0000000001f928d5
(It should be 2 instead of 0)
Incorrect block count for file 0000000001f9da23
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fa2e92
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fa89ba
(It should be 2 instead of 0)
Incorrect block count for file 0000000001faedb7
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fb1b67
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fb4f4e (It should be 1 instead of 0)
Incorrect block count for file 0000000001fbe608
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fc253a
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fc5330
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fcb863
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fcf4ab
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fd5586
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fe50ef (It should be 2 instead of 0)Incorrect block count for file 0000000001fe7501
(It should be 2 instead of 0)
Incorrect block count for file 0000000001fe9850
(It should be 2 instead of 0)
Incorrect block count for file 0000000001febbfc
(It should be 1 instead of 0)
Incorrect block count for file 0000000001fee257
(It should be 2 instead of 0)
Incorrect block count for file 0000000001ff4f92
(It should be 2 instead of 0)
Incorrect block count for file 0000000002016126
(It should be 2 instead of 0)
Incorrect block count for file 000000000201d55c
(It should be 2 instead of 0)
Incorrect block count for file 0000000002023b79(It should be 2 instead of 0)
Incorrect block count for file 000000000202a533
(It should be 2 instead of 0)
Incorrect block count for file 00000000020315b4
(It should be 2 instead of 0)
Incorrect block count for file 00000000020381d0
(It should be 2 instead of 0)
Incorrect block count for file 000000000203c6cb
(It should be 2 instead of 0)
Incorrect block count for file 0000000002045084
(It should be 2 instead of 0)
Incorrect block count for file 000000000204f9f7
(It should be 2 instead of 0)
Incorrect block count for file 0000000002056150
(It should be 2 instead of 0)
Incorrect block count for file 000000000205ec73(It should be 2 instead of 0)
Incorrect block count for file 0000000002065156
(It should be 2 instead of 0)
Incorrect block count for file 000000000243973b
(It should be 1 instead of 0)
Incorrect block count for file 0000000002440880
(It should be 1 instead of 0)
Incorrect block count for file 00000000027e20f5
(It should be 1 instead of 0)
Incorrect block count for file 0000000003ae6aff
(It should be 1 instead of 0)
Incorrect block count for file 0000000003af9c3e
(It should be 1 instead of 0)
Incorrect block count for file 0000000004ecca87
(It should be 1 instead of 0)Incorrect block count for file 0000000005695936
(It should be 1 instead of 0)
Incorrect number of thread records
Checking multi-linked files.
Checking Catalog hierarchy.
Checking Extended Attributes file.
Checking multi-linked directories.
Checking volume bitmap.
Volume Bit Map needs minor repair
Checking volume information.
Invalid volume free block count
(It should be 95145020 instead of 95145021)
The volume Iomega HDD needs to be repaired.
Error: Filesystem verify or repair failed.
Thanks for taking a look at this. Does this mean my external drive is toast?