The first steps was to return to reduced scanning, but eliminate all possibility of going more than 10°  below the limb. This was accomplished by some very careful analysis to insure sun safety. No position errors occurred while scanning 10° below the limb over four days. Therefore, the next step was to expand  the range to 20° below the limb. Within 20 minutes (and 30 limb scans), a position error occurred and instrument fault protection stowed the instrument. The error was determined to be a small (4-step)  position error. The next day, the scanning pattern was reduced to go only 10° below the limb. This was successful and  no further position errors have occurred as of this paper.  Discussion of Errors and Error Statistics  MCS has experiences 203 position errors. The errors fall into 5 groups according to when they occurred  (see above). The first error was prior to launch. The first flight family occurred in Dec. 2006, a second family in Jan. 2007, a third family in June 2007 and the final position error occurred in Oct. 2007. All of the errors have been characterized to the extent possible, given the limited in-flight telemetry.  Unfortunately, an extensive analysis of the instrument and spacecraft telemetry associated with the errors has been mostly unproductive, both on an individual basis and in statistical analyses. One of the difficulties in the investigation is that the specific slew with the position error is almost never  known. There is almost always at least a pair of suspect slews for any given position error. In some cases, there are many possible slews where the error could have occurred. And given the slew pairs are in opposite directions, in most cases, an undershoot on one slew or an overshoot on the other could be responsible for the identified error. The May and June diagnostic tests were set up to minimize this  uncertainty. But without an absolute position indicator, not all of the uncertainty could be removed.  However, there are a few significant points that the analysis did uncover.  Even though the errors families appear indistinguishable, various error-type subsets stand out:  - The five large errors (errors where pointing is off by more than 1 degree) all occurred in January. All of  these large errors are known to have occurred at elevation angles > 120°. Since slewing operations were stopped in Jan. 2007, the instrument was only slewed past 120° for ~20 minutes in October.  - Most of the pointing errors that could be measured are 4-step errors. The preponderance of the 4-step  errors is assumed to be due to the 4-phase nature of the MCS controller. At nominal speed, a four-step error could potentially be generated by an approximately 15 m-sec lasting signal disturbance. But there  are at least four errors that are 2-step errors (and a small family that may be 5 or 6 step errors). One  possible way of generating 2, 5 and 6 step errors is to have the error occur at the end of the slew.   - The time (or scanning) between individual errors is highly variable, ranging from 2 minutes (the first  scanning after re-initializing) to over 13 hours in one case. Even within a given time frame, the time between errors is highly variable (for example, the 13-hour interval followed a 2-minute interval). While  errors may have occurred on consecutive slews, they never occurred on more than 5% of the slews, and  in most periods, the frequency is below 0.1%. The general error frequency increased during the  December and January groups of errors. During the May/June diagnostic period, the error frequency decreased until the instrument reached an error free state using the current set of environmental  constraints. - No correlation of errors with any environmental condition has been found (at the resolution of the  available data). In particular, there are no significant temperature fluctuations. The only possible exception is the spacecraft bus voltage: For most of the MRO orbit, the voltage is at 32.5 V, but it dips as low as 28 V during the eclipse (slowly dropping at eclipse and then returning to 32.5 V immediately afterwards). There are relatively few errors at low voltages (since the bus is at 32.5 V most of the time). At most, the probability of an error at 28 V is twice that above 32 V, but this might not be statistically  significant. The life-test actuator (and the limited testing of the flight actuator), indicate there is a very abrupt transition between completely stalling (at 22.8 V) and running fine (at 22.9 V) with the micro  stepper controller. Thus, any in-flight voltage fluctuation should not cause errors. Due to the rapid  285