the MSDB log is about 15 GB whereas the data file is only 6 GB. Is there a way to shrink the MSDB log? Thanks
Make sure your MSDB is not in FULL recovery mode. If it is is in FULL recovery mode, change it SIMPLE before shrink it.
by default system database are in simple recovery mode. So you will not requried to shrink log as long you havent changed it to full.