From GpsWiki

Issues

These are widely reported possible issues with the PN-40. The fact that an issue is listed here does not mean the DeLorme is aware of it or working on it. In fact, there is no guarantee that it's a verified issue. Most of this information is based on forum posts.

Hardware

• 03/01/2009. One-piece USB cable shipped with unit. Several users report intermittent connectivity problems. Symptoms range from stalled waypoint transfers in T7 to failure to mount the removable USB drive in Map Transfer or Upload Field Notes modes. In some cases, using a different USB port may help. Wiggling the cable between the RF choke and the connector or pushing on the cable loop through the choke may change or alleviate the symptoms. Replacement two-piece cables solve the problem in almost every reported case.
• 03/01/2009. Battery polarity. Inserting the batteries in the wrong direction may cause the unit to subsequently fail to start. It's not clear if this results in permanent damage to the unit. See this thread for more information. DeLorme is aware of this issue.
• 03/01/2009. Unit fails to power up in unpredictable circumstances. There are circumstances where the unit fails to power up, even when batteries have not been reversed. In some cases, this appears to occur after the unit shuts down on its own with exhausted batteries. Seems to occur more frequently with alkalines than with other battery types. Leaving the unit without batteries over night has been reported to fix the problem in some cases. More information is available here and here.

Firmware

• 03/01/2009. v2.4 RTM/v2.5 beta 3. With v2.4, WAAS performance is poor. Most people do not see applied corrections (blue bars), let alone a WAAS lock (W under 3-D fix on the satellite page). Much improved with v2.5b3, but some users still report difficulty achieving WAAS lock.
• 03/01/2009. v2.5 beta 3. Unit sometimes fails to reacquire a fix after losing lock. Even in full view of the sky, satellite bars flash randomly for long periods without achieving a fix. Power cycling the unit clears the problem immediately.
• 03/02/2009. v2.5 beta 3. Geocaching. Unit sometimes logs an attempt on the wrong cache. While routing to one cache, view another. Subsequently logging an attempt logs it for the cache you viewed, not the one to which you were routing. Steps to reproduce the problem use Find to view the second cache. Not clear if the problem occurs if you view the second cache in other ways. DeLorme has acknowledged the problem and can reproduce it.
• 04/04/'2009. v2.5 beta 3. Problems archiving current track when full. If the current track fills and automatic archiving is enabled, track logging may stop when the switch occurs. In some cases, it stops for some minutes and resumes. In other cases, it stops permanently. In the latter situation, the tracks screen shows logging enabled, current track empty (0%), and the archived log does not show in the list. Manually archiving the current log (even though it appears empty) fixes the problem. Note that the manually archived log appears to contain the expected data. Unit was configured to automatically archive and to prompt for reset.
• 04/10/2009. v2.5b3. The info field for distance traveled seems to understate the actual distance traveled. Also, time moving times average speed moving does not equal distance traveled. Understating the distance traveled is a problem for everybody who cares about distance. Incorrect average speed while moving affects those who use device for fitness training.

Other Software

• 03/01/2009. Send to GPS plug-in IE v1.0 build 138407. Send to GPS dialog sometimes fails to locate the plug-in on the first try to send a particular cache. Occurs when attepting to send from the white pop-up balloon on the Google maps/geocaching maps page and may occur in other situations. Usually succeeds on the next try.