Hi lingesh waran,
Thanks for the screenshot. In the top line I see the message “no space left on device” and the error message says it failed to write to the hard drive. I think in that case it is because there is not enough memory left on the device to store the merged tiles, freeing up some memory should help. Another thing to check would be to make sure you have the write access on these folders (e.g. if you need to be an admin on your computer).
Let me know if that solved the issue!
I Had the same problem and now i Want to to merge the generated tiles but not to rebuild all the tiles again.
Is that posible? How?
Please see the answer in the other ticket that you have posted.