It is not at all specific to flashing Zorin OS.
Today I have exactly the same problem and the same “message of null” when I try flashing ubuntuxxx.iso or linuxmintxxx.iso to two different new USB keys.
(theubuntu iso file had been tested and used OK before on DVD with “brasero” as a burner)
Here is what can be read on Etcher Console:
Wed Dec 15 2021 19:31:49 GMT+0100 (heure normale d’Europe centrale) Write failed ({“image”:{“size”:2143289344,“name”:“linuxmint-20.2-mate-64bit.iso”,“hasMBR”:true,“partitions”:[{“offset”:315392,“size”:4063232,“type”:239,“index”:1}],“extension”:“iso”,“path”:"/home/yves/System_Images/Linux-Mint/linuxmint-20.2-mate-64bit.iso"},“drives”:[{“size”:7801405440,“isVirtual”:false,“enumerator”:“lsblk:json”,“logicalBlockSize”:512,“raw”:"/dev/sdh",“error”:null,“isReadOnly”:false,“displayName”:"/dev/sdh",“blockSize”:512,“isSCSI”:false,“isRemovable”:true,“device”:"/dev/sdh",“busVersion”:null,“isSystem”:false,“busType”:“USB”,“isCard”:null,“isUSB”:true,“devicePath”:"/dev/disk/by-path/pci-0000:00:14.0-usb-0:2:1.0-scsi-0:0:0:0",“mountpoints”:,“description”:“Linux Mint 20.2 MATE 64-bit Innostor Innostor”,“isUAS”:null,“partitionTableType”:“mbr”}],“driveCount”:1,“uuid”:“fac5066e-dad8-4256-a4b5-3123ca9c8c68”,“status”:“failed”,“flashInstanceUuid”:“fac5066e-dad8-4256-a4b5-3123ca9c8c68”,“error”:{},“sample”:0.1,“applicationSessionUuid”:“28d950d1-53a3-4d80-825a-9de0da53d826”,“flashingWorkflowUuid”:“d8712459-508a-413b-a088-8233cdf3b13f”})
gui.js:46 {“stack”:“TypeError: Cannot read property ‘message’ of null\n at file:///tmp/.mount_balenajW5sCY/resources/app/generated/gui.js:351:4728\n at async withTmpFile (file:///tmp/.mount_balenajW5sCY/resources/app/generated/gui.js:1:344288)\n at async elevateCommand (file:///tmp/.mount_balenajW5sCY/resources/app/generated/gui.js:351:4236)\n at async Server. (file:///tmp/.mount_balenajW5sCY/resources/app/generated/gui.js:351:8340)”,“message”:“Cannot read property ‘message’ of null”,“image”:“linuxmint-20.2-mate-64bit.iso”}
Regards