Project Raster: Error 000289 Failed to alter spatial reference

[CarinaZacharias]

Hi,

I have a problem that does not seem to be answered by any previous forum entry or ESRI support pages. I simply tried to use the Project Raster tool to reproject a raster layer. It has worked before (with a different layer), but now I get this error:

In the description it says: "The spatial reference of the dataset cannot be altered. The dataset may be in use by another application and therefore locked." But I don't really know what to make of this.

Please, can anybody help? Thanks very much!

[DanPatterson_Retired]

it is already projected... is this some web sourced file? like web Mercator?  Check with the origin of the file, it was obviously projected, you just need to find out which one, then use Define Projection to fix the erroneous definition that exists now.

[CarinaZacharias]

Perfect, thanks so much for your help!