Arduino: 1.8.0 (Windows 10), Board: "Arduino/Genuino Uno"

c:\program files (x86)\arduino\hardware\tools\avr\bin../lib/gcc/avr/4.9.2/../../../../avr/bin/ar.exe: unable to rename 'core\core.a'; reason: Permission denied

exit status 1 Error compiling for board Arduino/Genuino Uno.

This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences.

  • forum.arduino.cc/index.php?topic=134161.0 seems to contain multiple possible solutions. Run Arduino as Administrator. Create a new sketch, and copy all code to this new sketch. Something with the %tmp% directory. – Gerben Jan 4 '17 at 19:39
  • Code file has full permissions and access. Running the IDE as administrator makes no difference. Same error message for everything (blink ++++) as above. re-install of IDE made no difference. – grtblu Jan 5 '17 at 22:35
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    It looks like @grtblu and ArduinoAngryAtMe are the same person. It is confusing when someone else replies to a comment. It would help if you remembered your login credentials and replied as the OP. – Nick Gammon Feb 5 '17 at 9:28
  • I suggest downloading the IDE into a folder which is not in Program Files. Put it in Documents or some such place. – Nick Gammon Feb 5 '17 at 9:29
  • There are some reports of this error in the Arduino IDE issue tracker: github.com/arduino/Arduino/issues/5616 and github.com/arduino/Arduino/issues/4683 where it was found to be caused by antivirus software. – per1234 Oct 4 '17 at 13:25

Try locating the code file in explorer.exe, go to its properties and check if the system has full access to the file. Just to be sure, run the Arduino IDe as an administrator.

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  • I understand the logic in running as the administrator and its usually a good solution, but it may cause problems because the IDE reads and writes to folders within the user's profile and the Administrator MAY not have permissions to these files, so you need to check that as well. It would be better to give users the permissions they need on the Arduino IDE folders and registry hives. – Code Gorilla Jul 6 '17 at 7:08

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