tl;dr: the D1 mini's usbserial interface is a little sketchy and macOS doesn't cope well. You need to install the driver from wch.cn. direct link to CH341SER_MAC.ZIP
SHA-512 sum (copy whole line, run pbpaste | shasum -c in your download directory to check):
efb25faeb87d66a10e284629231fad7ebfbdbf2c2a50ed9b35f8dd9793398ff79df3da3312367dbc497dc62103195bc4eaf6399f8084f442bb1d1a7a51551eac *CH341SER_MAC.ZIP
When plugging a Wemos D1 mini via USB into a Mac running macOS High Sierra (10.13) -- and possibly other versions -- I experienced an immediate and repeatable crash.
Examining the crash report offered on reboot, I observed the following line:
last loaded kext at 79125794784: com.wch.usbserial 1 (addr 0xffffff7f89fbe000, size 36864)
This made me suspect that a usbserial driver might be needed; DuckDuckGo searches confirmed from several sources that a driver for the WCH usbserial interface was required for macOS. Examining the vendor's website revealed a download for a Mac driver.
- Ensure Wemos D1 mini is disconnected
- Using the vendor's driver download page, download
CH314SER_MAC.ZIP - Unpack the zip. From the created folder, run
CH34x_Install_V1.4.pkg; this will require a restart - After restart is complete, reconnect Wemos D1 mini
If no crash or restart occurs after reconnection, you've solved the problem.