First of all, make sure your Windows User has write access to the Anima project folder that is being used by the Anima Drop. If you user has write access there, then this error is most likely related to a problem with the Anima project’s resource cache.
When the cache is incomplete or corrupted for some reason [crashes, network interruptions], some assets cannot be properly included in there and may end up causing these R/W errors, or making the plugin to show “Missing Actors” instead of the correct models. In these cases, we recommends fully regenerating the resource cache for that Anima project.
Please, follow this procedure on the project you’re using with Anima Drop:
Close everything using that project
Close Anima Designer and 3ds Max [and any other machine that might be using the same Anima project].
Delete the existing resource cache
Go to your Anima project folder used by Anima Drop.
Open the “resource_cache” subfolder.
Delete all files inside it [typically one or more pack.bin files].
Force Anima to rebuild the cache
Open Anima Designer and load that same project.
Create a new empty scene in this project [if you only used Drop before, you may see no scenes, but you can still create one].
Pick a model that has not been used yet in this project [or download a new one] and drop it into the scene.
Use File > Save all.
Anima will then start rebuilding the resource cache for all assets used in all scenes in that project. Depending on how big is your scene, this can take a few minutes.
When done, test again to add a new model in 3ds Max with Anima Drop:
Reopen 3ds Max
Open your scene
Then open Anima Drop
Try dropping the same models again.
If, after a full cache rebuild, the same error still happens, please open a support request and share the project and error details with us there.
You will find more info about the resource cache and missing actors in the links below:
We have been able to replicate the same issue in our testing environment, and it is already being tracked in the Developers backlog (AN-1159). It should be fixed in the next Anima update.