This issue usually arises if you have assigned a too small or too large amount of RAM to Calamus.
Relaunch Calamus while pressing the [Ctrl] key (bottom left border of your keyboard).
Now you should see the dialog Calamus Parameters
. There you find an input field Maximum Memory
. Enter a value smaller than 1,000. Usually you should be fine with the default value of 128 MB.
Then click on [Save] to store the change. You now can launch Calamus with a click on [OK].
Background information: Many users want to do Calamus a favor by assigning as much memory as possible. But after all, Calamus still is a TOS program which cannot handle those large amounts of RAM. TOS programs can address a maximum of 1 GB (1,024 MB), but Calamus should also do without a certain amount of RAM in favor of the built-in emulator. If you have to handle very large documents, you'd better use the OPI manažer to swap large amounts of image data to your hard drive instead.