Access denied upon upload

[nicodonte]

Uploading LittleFS filesystem
C:\Users\nicod\AppData\Local\Arduino15\packages\esp8266\tools\python3\3.7.2-post1/python3.exe C:\Users\nicod\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.1.2/tools/upload.py --chip esp8266 --port COM5 --baud 115200 write_flash 3145728 C:\Users\nicod\AppData\Local\Temp\tmp-12172-OcGfrVVmO131-.littlefs.bin
esptool.py v3.0
Serial port COM5

A fatal esptool.py error occurred: could not open port 'COM5': PermissionError(13, 'Access denied.', None, 5)
Completed upload.

[nicodonte]

Solved!! The serial monitor needed to be closed before uploading files.