I am not aware about this particular issue.
Based on the error I assume it has to do with the image collections you add to a module. Check if any of the image collections you added is blocking your merge.
In general we faced a lot of issues while merging as well. What we noticed is, when things goes wrong in Mendix merge, we also try to do that with Tortoise SVN, i.e outside Mendix. Sometimes, it went perfectly fine without issues.
Also SVN merging will give more bit more meaningful statements and reasons when issue happens, which helped us until now to figure out what happened and fix it.
I never saw this issuem but i would do in this case: remove the main line from my system, reload a fresh copy and retry.
If that doesn't work: if the change is small, dont do a merge but simply redo the change in main by hand.
In other cases, i think it is wise to create a support ticket, because it does sounds like a bug to me.
I hope this helps.
I have the exact same problem. How did you solve this?
Hi Vinesh, This issue is due to a bug in Mendix Studio 8.13 & 8.14 version. This issue is resolved in 8.15 version, upgrade your project to 8.15.1 version and try it will work. We just completed our merge, it's working.