Can't open document after changing links

[coendegoey]

First of all, i'm not really experienced in using Indesign. I've been working on a document that has to be printed in grayscale and handed in as pdf. Therefore, the printer asked me to convert all linked images to grayscale.

In order to do this I used the packaged file I made of the Indesign document and converted the whole image-map to grayscale in Photoshop. After this, I tried to re-open the Indesign document but in some way, it didn't give a preview of the document. The program also has troubles opening the original document because it doesn't give a good preview either. The document is still intact because i'm still able to make a pdf file out of it.

Does anyone know something about this problem?

Coen