A person asked if MesaExif 1.0.5 runs on Sierra?
Condition:
- Sierra
- NG:
MacHD>Users>bens_imac>Picture>2010>2010-04-25>whateverIMG.jpg
- OK:
MacHD>Users>bens_imac>Picture>test.jpg
Since I have not yet recreated the trouble so far, my recommendation is for him to cancel the purchase at App Store or via Apple Support first of all.
I have verified the conditions as follows:
My Mac is iMac Mid 2011 with 2.5GHz Intel/24GB, macOS Sierra version 10.12, English. Though it has 24GB as of today, it was 12GB at the MesaExif 1.0.5 release.
1. I set following picture files in 2010-04-25 including whateverIMG.jpg.

2. I clicked MesaExif, selected the picture files as following.

3. MesaExif works.

4. The version is 1.0.5.

p.s. I am wondering whether or not the jpg file or the file info is appropriate with MesaExif 1.0.5. What about the exported file from Preview?
p.s.
- OK: Local disk / iCloud
- NG: Dropbox / LAN disk
I understand the trouble phenomenon and successfully recreated it with Dropbox and LAN disk. However iCloud is OK. I guess it occurs when MesaExif can not generate the appropriate file path that is given by the standard NSOpenPanel interface via Dropbox / LAN disk. If NSOpenPanel returns error to MesaExif, MesaExif shows the error dialog as you see. This is the case, I guess.
I will investigate the cause further. But I am not sure when I will be able to fix it at this moment.
I am planning to update MesaExif with Xcode 8 and Swift 3 by the end of December after MesaClip release. I will investigate the error further by the update release.