Here is the global_prefs.xml. It was updated this morning. I assume that the rows that matter are those highlighted which look correct and are the same as those on the systems that are working. There are other computers using some of the other profiles but I am not concerned about those.

Could I un-install the Boinc manager from the failing system and re-install without losing the work in progress? This system has many versions of the client while both of the others are less than 1 year old.

<global_preferences>
<source_project>http://www.worldcommunitygrid.org/</source_project>
<source_scheduler>https://grid.worldcommunitygrid.org/boinc/wcg_cgi/fcgi</source_scheduler>
<mod_time>1292581326</mod_time>
<cpu_scheduling_period_minutes>120</cpu_scheduling_period_minutes>
<disk_interval>60.0</disk_interval>
<disk_max_used_gb>4.0</disk_max_used_gb>
<disk_max_used_pct>80.0</disk_max_used_pct>
<disk_min_free_gb>0.5</disk_min_free_gb>
<idle_time_to_run>3.0</idle_time_to_run>
<max_bytes_sec_down>0.0</max_bytes_sec_down>
<max_bytes_sec_up>0.0</max_bytes_sec_up>
<max_cpus>16</max_cpus>
<run_if_user_active/>
<cpu_usage_limit>100.0</cpu_usage_limit>
<ram_max_used_busy_pct>50.0</ram_max_used_busy_pct>
<ram_max_used_idle_pct>75.0</ram_max_used_idle_pct>
<work_buf_min_days>1.0</work_buf_min_days>
<end_hour>0</end_hour>
<net_end_hour>7</net_end_hour>
<net_start_hour>1</net_start_hour>
<run_on_batteries/>
<start_hour>0</start_hour>
<vm_max_used_pct>50.0</vm_max_used_pct>
<work_buf_additional_days>2.0</work_buf_additional_days>
<suspend_if_no_recent_input>0.0</suspend_if_no_recent_input>
<max_ncpus_pct>100.0</max_ncpus_pct>
<daily_xfer_period_days>0</daily_xfer_period_days>
<daily_xfer_limit_mb>0.0</daily_xfer_limit_mb>
<suspend_cpu_usage>80.0</suspend_cpu_usage>
<leave_apps_in_memory/>
<venue name="home">
<cpu_scheduling_period_minutes>120</cpu_scheduling_period_minutes>
<disk_interval>60.0</disk_interval>
<disk_max_used_gb>4.0</disk_max_used_gb>
<disk_max_used_pct>80.0</disk_max_used_pct>
<disk_min_free_gb>0.5</disk_min_free_gb>
<end_hour>0</end_hour>
<idle_time_to_run>3.0</idle_time_to_run>
<max_bytes_sec_down>0.0</max_bytes_sec_down>
<max_bytes_sec_up>0.0</max_bytes_sec_up>
<max_cpus>16</max_cpus>
<net_end_hour>0</net_end_hour>
<net_start_hour>0</net_start_hour>
<run_if_user_active/>
<run_on_batteries/>
<start_hour>0</start_hour>
<cpu_usage_limit>100.0</cpu_usage_limit>
<ram_max_used_busy_pct>75.0</ram_max_used_busy_pct>
<ram_max_used_idle_pct>75.0</ram_max_used_idle_pct>
<work_buf_min_days>2.0</work_buf_min_days>
<vm_max_used_pct>75.0</vm_max_used_pct>
<work_buf_additional_days>5.0</work_buf_additional_days>
<suspend_if_no_recent_input>0.0</suspend_if_no_recent_input>
<max_ncpus_pct>100.0</max_ncpus_pct>
</venue>
<venue name="school">
<cpu_scheduling_period_minutes>120</cpu_scheduling_period_minutes>
<disk_interval>60.0</disk_interval>
<disk_max_used_gb>4.0</disk_max_used_gb>
<disk_max_used_pct>80.0</disk_max_used_pct>
<disk_min_free_gb>0.5</disk_min_free_gb>
<end_hour>0</end_hour>
<idle_time_to_run>3.0</idle_time_to_run>
<max_bytes_sec_down>0.0</max_bytes_sec_down>
<max_bytes_sec_up>0.0</max_bytes_sec_up>
<max_cpus>16</max_cpus>
<net_end_hour>0</net_end_hour>
<net_start_hour>0</net_start_hour>
<run_if_user_active/>
<run_on_batteries/>
<start_hour>0</start_hour>
<cpu_usage_limit>100.0</cpu_usage_limit>
<ram_max_used_busy_pct>75.0</ram_max_used_busy_pct>
<ram_max_used_idle_pct>75.0</ram_max_used_idle_pct>
<work_buf_min_days>0.5</work_buf_min_days>
<vm_max_used_pct>75.0</vm_max_used_pct>
<work_buf_additional_days>0.0</work_buf_additional_days>
<suspend_if_no_recent_input>0.0</suspend_if_no_recent_input>
</venue>
<venue name="work">
<cpu_scheduling_period_minutes>120</cpu_scheduling_period_minutes>
<disk_interval>60.0</disk_interval>
<disk_max_used_gb>4.0</disk_max_used_gb>
<disk_max_used_pct>80.0</disk_max_used_pct>
<disk_min_free_gb>0.2</disk_min_free_gb>
<end_hour>0</end_hour>
<idle_time_to_run>0.0</idle_time_to_run>
<max_bytes_sec_down>0.0</max_bytes_sec_down>
<max_bytes_sec_up>0.0</max_bytes_sec_up>
<max_cpus>16</max_cpus>
<net_end_hour>0</net_end_hour>
<net_start_hour>0</net_start_hour>
<run_if_user_active/>
<run_on_batteries/>
<start_hour>0</start_hour>
<cpu_usage_limit>100.0</cpu_usage_limit>
<ram_max_used_busy_pct>75.0</ram_max_used_busy_pct>
<ram_max_used_idle_pct>75.0</ram_max_used_idle_pct>
<work_buf_min_days>2.0</work_buf_min_days>
<vm_max_used_pct>75.0</vm_max_used_pct>
<work_buf_additional_days>5.0</work_buf_additional_days>
<suspend_if_no_recent_input>0.0</suspend_if_no_recent_input>
<max_ncpus_pct>100.0</max_ncpus_pct>
</venue>
</global_preferences>

You are not testing my patience as you are trying to help. Thanks for that.

The answer was that in the client_state.xml (handle with extreme care) I had:

<user_network_request>1</user_network_request>

I stopped the client, opened the file, changed the value to 2, saved the file and then restarted. The client then gave me the "Suspending network activity - time of day" message.

So all solved by the looks of it. As long as I can survive on my remaining bandwidth allowance until Christmas day I will have a higher allowance and I can switch back to uploading on completion.

Thank you.