Running out of file descriptors

[toddkrein]

I'm getting a wierd error when I try to rerun my program:

exec(open("junk.py").read(),globals())
hello
I am loading
Starting main()
Starting MQTT
<MQTTClient object at 3fff0720>
Setting the date/RTC
2000/01/01 0:10:55
2000/01/01 0:10:55
Running off the end
exec(open("junk.py").read(),globals())
E (658885) vfs_fat: open: no free file descriptors
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OSError: [Errno 2] ENOENT

a ^D soft reset seems to fix it, but...