this is the log
21:18:19:754 [APP] Download patch info file
21:18:19:762 [ZUpdate] Start update.
21:18:19:768 [ZFileTransfer] Download file : patch.xml.comp to ./patch.xml.comp
21:18:2046 [ZFileTransfer] Download successfully complete.
21:18:2086 [ZUpdate] Get update info.
21:18:20:509 [ZUpdate] Get update info successfully complete.
21:18:20:522 [ZUpdate] Check valid from patch list.
21:18:20:595 [ZUpdatePatchNode] Needs to update : Gunz.exe
21:18:2552 [ZUpdate] Check valid from patch list successfully complete.
21:18:2559 [ZUpdate] + Total patch file count : 1
21:18:2565 [ZUpdate] + Total patch file size : 4031488 bytes
21:18:2572 [APP] Exist patch file(s)
21:18:2578 [APP] Start file updating...
21:18:2585 [ZUpdate] Patch files.
21:18:2591 [ZFileTransfer] Download file : Gunz.exe to D:\New folder\Gunz\Freestyle GunZ V8\PATCH\Gunz.exe_
21:180:883 [ZFileTransfer] Download successfully complete.
21:181:985 [ZUpdate] Successfully download '.\PATCH\Gunz.exe_'
21:182:002 [ZUpdate] Patch files successfully complete.
21:182:016 [ZUpdate] Move patch files.
21:182:225 [ZUpdate] ERROR : Invalid CRC '.\PATCH\Gunz.exe_'
21:182:231 [ZUpdate] Move patch files successfully complete.
21:182:238 [ZUpdate] ERROR : Cannot move patch files.
21:182:244 [APP] ERROR - Update fail
21:182:250 [APP] Updater error message :
Invalid CRC from the downloaded patch file. : .\PATCH\Gunz.exe_
[Tip] Please check your anti-virus program and firewall running on your system.
Tried switching off firewall and putting on the exception list.