Unknown error in line 17

I wonder why only a tiny fraction of all my images apperar on the map. So I did a scan-photos with -vvv After a while the execution stopped with

In Exception.php line 17:
                                                                   
  [Icewind\SMB\Exception\Exception] 
  Unknown error () for /#recycle/Schulungen/Sicherung/Schulungen/ActiveDirectory/milupa/Präsentation/Beispiele/ADSI_Zu_Gruppe_Hinzuf_gen/ADSI_Zu_Gruppe_Hinzu
  f_gen/bin


Exception trace:
  at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Exception/Exception.php:17
 Icewind\SMB\Exception\Exception::unknown() at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Exception/Exception.php:35
 Icewind\SMB\Exception\Exception::fromMap() at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Wrapped/Parser.php:88
 Icewind\SMB\Wrapped\Parser->checkForError() at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Wrapped/Share.php:441
 Icewind\SMB\Wrapped\Share->parseOutput() at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Wrapped/Share.php:152
 Icewind\SMB\Wrapped\Share->dir() at /var/www/nextcloud/apps/files_external/3rdparty/icewind/smb/src/Wrapped/Share.php:171
 Icewind\SMB\Wrapped\Share->stat() at /var/www/nextcloud/apps/files_external/lib/Lib/Storage/SMB.php:179
 OCA\Files_External\Lib\Storage\SMB->getFileInfo() at /var/www/nextcloud/apps/files_external/lib/Lib/Storage/SMB.php:297
 OCA\Files_External\Lib\Storage\SMB->stat() at /var/www/nextcloud/lib/private/Files/Storage/Common.php:187
 OC\Files\Storage\Common->filemtime() at /var/www/nextcloud/apps/files_external/lib/Lib/Storage/SMB.php:397
 OCA\Files_External\Lib\Storage\SMB->hasUpdated() at /var/www/nextcloud/lib/private/Files/Storage/Wrapper/Wrapper.php:379
 OC\Files\Storage\Wrapper\Wrapper->hasUpdated() at /var/www/nextcloud/lib/private/Files/Storage/Wrapper/Availability.php:384
 OC\Files\Storage\Wrapper\Availability->hasUpdated() at /var/www/nextcloud/lib/private/Files/Storage/Wrapper/Wrapper.php:379
 OC\Files\Storage\Wrapper\Wrapper->hasUpdated() at /var/www/nextcloud/lib/private/Files/Cache/Watcher.php:127
 OC\Files\Cache\Watcher->needsUpdate() at /var/www/nextcloud/lib/private/Files/View.php:1342
 OC\Files\View->getCacheEntry() at /var/www/nextcloud/lib/private/Files/View.php:1445
 OC\Files\View->getDirectoryContent() at /var/www/nextcloud/lib/private/Files/Node/Folder.php:100
 OC\Files\Node\Folder->getDirectoryListing() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:322
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:332
 OCA\Maps\Service\PhotofilesService->gatherPhotoFiles() at /var/www/nextcloud/apps/maps/lib/Service/PhotofilesService.php:67
 OCA\Maps\Service\PhotofilesService->rescan() at /var/www/nextcloud/apps/maps/lib/Command/RescanPhotos.php:80
 OCA\Maps\Command\RescanPhotos->rescanUserPhotos() at /var/www/nextcloud/apps/maps/lib/Command/RescanPhotos.php:71
 OCA\Maps\Command\RescanPhotos->execute() at /var/www/nextcloud/3rdparty/symfony/console/Command/Command.php:255
Symfony\Component\Console\Command\Command->run() at /var/www/nextcloud/3rdparty/symfony/console/Application.php:915         
 Symfony\Component\Console\Application->doRunCommand() at /var/www/nextcloud/3rdparty/symfony/console/Application.php:272    
 Symfony\Component\Console\Application->doRun() at /var/www/nextcloud/3rdparty/symfony/console/Application.php:148           
 Symfony\Component\Console\Application->run() at /var/www/nextcloud/lib/private/Console/Application.php:214                  
 OC\Console\Application->run() at /var/www/nextcloud/console.php:99                                                          
 require_once() at /var/www/nextcloud/occ:11

There is no such file nor directory "Icewind" - there are quit a few Umlauts öäü in my file names - and they mix UTF8 and Latin1 encoding for historical reasons. In the bin directory I left some old Windows exes ...

What's wrong?
Is there a way to configure/restrict scanning to certain directories where the photos are?

Start with apps/maps/lib/Command/RescanPhotos.php and apps/maps/lib/Service/PhotofilesService.php, following the gatherPhotoFiles() path shown in the trace. Reproduce the failure with the photo rescan command against the reported SMB path and inspect how the error from files_external is handled. Done means the rescan behavior and any directory restriction are clearly defined and verified for these paths.