Lines Missing When Vector pdf Opened

[sarahp57481846]

Hello there.

I am trying to open a vector diagram created with a different software within my company.  (I'm not sure what software it was made with but I can find out.)

When I open the pdf with the vector diagram, half the lines are invisible. A select all shows that they exist, and are selectable.

I try to change the color of the outline and also fill but it only effects the lines that were visible in the first place. 

Is there anything that can be done? Could it possibly be a security feature from the other software?

Thank you for your advice!

Sarah

[PrepressPro1]

Is it possible for you to post a sample illustrator file with this anomaly? 

[sarahp57481846]

I found that opening the file itself and selecting "open with Illustrator" opens the file fine.

Opening the file through illustrator reveals the issue described above.

I'll be using the Open With method, but it is pretty obnoxious.

PrepressPro1​  I would rather not share the doc, it's a plan drawing of one of our products.  Thank you for your willingness to help though!

[sarahp57481846 · Accepted solution]

Selecting the entire drawing and making it into a compound path also solved the problem.