I encountered this freak error when trying Meteor for the first time on my Windows 7 system.
Solution?
A. Create your Meteor project in C:/ instead of C:/users/user/documents/meteor or whatever!
This one worked for me. I don't see the logic behind it but I'm just glad it's running now.
B. Erase the /local/db/mongodb.lock file
This had worked for other people.
C. Reset your meteor project
Type mongo reset in terminal at your meteor project folder. This will reset your database!!
Solution?
A. Create your Meteor project in C:/ instead of C:/users/user/documents/meteor or whatever!
This one worked for me. I don't see the logic behind it but I'm just glad it's running now.
B. Erase the /local/db/mongodb.lock file
This had worked for other people.
C. Reset your meteor project
Type mongo reset in terminal at your meteor project folder. This will reset your database!!