Unable to copy data from Mac to external HDD using FFS

[udhayagen]

Hello Team - I have been using ffs for years without any issues in windows laptop. Recently, got the mac book and copied all data from HDD to mac locally without any issues...so far so good...

I have been using a mac for a couple of months and now, want to sync back the latest data from the mac to the same external HDD. However, I'm hitting an issue (posted below) and none of the files are getting copied. I have ensured that HDD has sufficient space and required privileges too..
ANy help on this regard much appreciated

20:00:37 Warning Cannot set directory locks for the following folders:
Cannot write file "/Volumes/UdayRam/uday_documents/sync.ffs_lock".
EROFS: Read-only file system [open]
20:00:55 Info Comparison finished: 15,038 items found | Time elapsed: 00:00:17
20:01:06 Warning Cannot set directory locks for the following folders:
Cannot write file "/Volumes/UdayRam/uday_documents/sync.ffs_lock".
EROFS: Read-only file system [open]
20:01:06 Info Creating file "/Volumes/UdayRam/uday_documents/New.txt"
20:01:14 Info Cannot write file "/Volumes/UdayRam/uday_documents/New~bd91.ffs_tmp".
EROFS: Read-only file system [open]
-> Retrying operation...
20:03:57 Error Cannot write file "/Volumes/UdayRam/uday_documents/New~fd57.ffs_tmp".
EROFS: Read-only file system [open]

[xCSxXenon]

Your external is set to read-only for some reason. It has nothing to do with FFS unfortunately.
https://www.google.com/search?q=mac+os+read+only+file+system

[udhayagen]

xCSxXenon - Thank you so much for rapid response. I have quickly verified that I have read and write permission. However, I also see it is Locked which is greyed out...