I am using Solidcam with Mach 3.

Plunging problem

I have created a simple set of operations.
the first operation is a rough cut. The operation was performed as expected except for 2 unexpected events. Right at the beginning of the operation the tool plunged 2mm and went to the corner of the stock. It then stayed at this Z-2mm level and went to the centre of the stock where it needed to cut a pocket. This meant that I had grooves on the surface of the part that were not meant to be there. Then, at the end of the operation the tool plunged 2mm again and went off to the corner of the stock adding another unwanted groove.

The second operation was a finishing cut with a different bit. This operation was good.

The third operation was a detail cut with a smaller bit. This operation was good.

The 4th operation was a profiling cut - to cut out the part from the stock. This operation worked ok except for a big problem at the beginning. The tool plunged 8mm from the zero point and then went out to the corner of the stock cutting an 8mm deep groove. Luckily the material was wood and I had set the feed quite slow so it didnt damage anything.

These problems in the operations came at the beginning and the end of the operation cycles and both seemed unnecessary and random. I have attached the part files in case this offers any insight.

File loss problem

I was working on the part file (above). This part is to be turned over in the CNC machine and the back will be machined. I created another file which had all the toolpaths for the machining of the back of the part. I saved this file, closed it and opened up the first file so that I could export the G codes. I then went to open up the second part file again. I went to 'Recent Solidcam parts' in the Solidcam drop down menu in Solidworks. An error came up which said something to the effect of 'Part is missing or deleted'. I checked the recycle bin in case I had unwittingly deleted the file. I also searched the hard drive in case it had moved somewhere. However the part is well and truely missing.
Has this happened to anyone else and how can I avoid it happening again?

Thanks for your help everyone!