Apparently this is a Dymo problem that has been known for about a month. Fortunately, if appears you can downgrade the driver to version - 8.3.1.1533 and it appears to work for some. The downgrade works on my system! Thanks for MacRumors troublador for the fix! You can find the install file link there as well.
Dear Mel,
Unfortunately our software is currently not supported by OS X Yosemite. The Mac OS is nearing its final testing stages but has not official been released. However, our developers are actively working on the issue, so that when the OS update is released the software and LabelWriters will be compatible with it. We do not have an exact ETA for the release date of the update as of yet. We are fully aware of the issue and are working towards a solution for our customers. Hopefully this email has answered your questions regarding this issue. If you have any other questions or concerns feel free to respond to this email, and also thank you for choosing DYMO.
Thank you,
Christopher
DYMO Brands Consumer Relations
877-724-8324