The BOINC client also attempts to allocate disk space to the various projects you attach to based on their resource shares, and the nature of whether their files would require download again if the client deleted them. You said you are running three projects. What are the resource shares between them?

The client application has been enhancing this balancing act between projects, and you are running a rather new client, but not the 6.2.18 nor the 5.10.45 that are currently recommended. Have you tried running one of the recommended versions?

There is enough disk space but rosetta is still complaining. The last time I had this error I increased the disk usage by setting a higher limit in local preferences. This shouldn't be necessary because BOINC already can use 470MB at the moment.

<working_global_preferences>
 <global_preferences>
   <disk_max_used_gb>0.500000</disk_max_used_gb>
   <disk_max_used_pct>80.000000</disk_max_used_pct>
   <disk_min_free_gb>1.000000</disk_min_free_gb>
 </global_preferences>
</working_global_preferences>
<disk_usage>
   <d_boinc_used_total>49059954.000000</d_boinc_used_total>
   <d_boinc_used_project>18298242.000000</d_boinc_used_project>
</disk_usage>

<scheduler_version>601</scheduler_version>
<master_url>http://boinc.bakerlab.org/rosetta/</master_url>
<request_delay>242.400000</request_delay>
<message priority="high">No work sent</message>
<message priority="high">There was work but you don't have enough disk space allocated.</message>
<message priority="high">An additional 47 MB is needed.</message>