Hi Luc de Hemptinne. I've seen a similar problem regarding a Norton kid protection product.

Check for a Profile that you may have installed to disable browsers. Settings > General, near the end of General. Look for Profile or Device Management. Tap on the profile and you can delete it.

Léonie -- I've crashed so often that the log is very long.  You asked for only the last 50 lines, so I didn't go back to the beginning.  This is the beginning of my long crash log:

Process:               Photos [2802]

Path:                  /Applications/Photos.app/Contents/MacOS/Photos

Identifier:            com.apple.Photos

Version:               3.0 (3251.12.190)

Build Info:            PhotoApp-3251012190000000~1

Code Type:             X86-64 (Native)

Parent Process:        ??? [1]

Responsible:           Photos [2802]

User ID:               501

Date/Time:             2018-01-12 14:36:22.713 -0500

OS Version:            Mac OS X 10.13.2 (17C88)

Report Version:        12

Anonymous UUID:        9B11447F-D9C5-5A93-419D-F18136765B7B

Time Awake Since Boot: 14000 seconds

System Integrity Protection: enabled

Crashed Thread:        10  Dispatch queue: GL0.low.run

Exception Type:        EXC_BAD_ACCESS (SIGBUS)

Exception Codes:       KERN_PROTECTION_FAILURE at 0x000070000595eff8

Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Bus error: 10

Termination Reason:    Namespace SIGNAL, Code 0xa

Terminating Process:   exc handler [0]

VM Regions Near 0x70000595eff8:

    Stack                  00007000058dc000-000070000595e000 [  520K] rw-/rwx SM=COW  thread 9

--> STACK GUARD            000070000595e000-000070000595f000 [    4K] ---/rwx SM=NUL  stack guard for thread 10

    Stack                  000070000595f000-00007000059e1000 [  520K] rw-/rwx SM=COW  thread 10

Thread 0:: Dispatch queue: com.apple.main-thread

0   libsystem_kernel.dylib         0x00007fff532bd7c2 mach_msg_trap + 10

1   libsystem_kernel.dylib         0x00007fff532bccdc mach_msg + 60

2   com.apple.CoreFoundation       0x00007fff2b928355 __CFRunLoopServiceMachPort + 341

3   com.apple.CoreFoundation       0x00007fff2b9276a7 __CFRunLoopRun + 1783

4   com.apple.CoreFoundation       0x00007fff2b926d23 CFRunLoopRunSpecific + 483

5   com.apple.HIToolbox           0x00007fff2ac3ee26 RunCurrentEventLoopInMode + 286

6   com.apple.HIToolbox           0x00007fff2ac3eb96 ReceiveNextEventCommon + 613

7   com.apple.HIToolbox           0x00007fff2ac3e914 _BlockUntilNextEventMatchingListInModeWithFilter + 64

8   com.apple.AppKit               0x00007fff28f09f5f _DPSNextEvent + 2085

9   com.apple.AppKit               0x00007fff2969fb4c -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044

10  com.apple.AppKit               0x00007fff28efed6d -[NSApplication run] + 764

11  com.apple.AppKit               0x00007fff28ecdf1a NSApplicationMain + 804

12  libdyld.dylib                 0x00007fff53177115 start + 1

Thread 1:: Dispatch queue: temp _renderVersionToSize queue

0   libsystem_kernel.dylib         0x00007fff532bd7fe semaphore_wait_trap + 10

1   libdispatch.dylib             0x00007fff5314d82e _dispatch_sema4_wait + 16

2   libdispatch.dylib             0x00007fff53145911 _dispatch_semaphore_wait_slow + 101

3   com.apple.photo.PAImaging     0x00007fff493408be -[PAExportService synchronouslySubmitRequest:onQueue:] + 821

4   com.apple.photo.PAImagingCore 0x00007fff4957d76c -[PAExportImageRequest(Dispatch) synchronouslySubmitOnQueue:] + 80

5   com.apple.photo.PAImaging     0x00007fff494717e5 __72-[PAPreviewMaker _renderVersionToSize:description:canceler:failureCode:]_block_invoke + 41

6   libdispatch.dylib             0x00007fff53145591 _dispatch_call_block_and_release + 12

7   libdispatch.dylib             0x00007fff5313dd50 _dispatch_client_callout + 8

8   libdispatch.dylib             0x00007fff5315231c _dispatch_queue_serial_drain + 907

9   libdispatch.dylib             0x00007fff531450fd _dispatch_queue_invoke + 373

10  libdispatch.dylib             0x00007fff53152f02 _dispatch_root_queue_drain_deferred_wlh + 332

11  libdispatch.dylib             0x00007fff53156d16 _dispatch_workloop_worker_thread + 880

12  libsystem_pthread.dylib       0x00007fff53402033 _pthread_wqthread + 980

13  libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 2:: Dispatch queue: PAPreviewWriter Render Queue

0   libsystem_kernel.dylib         0x00007fff532bd816 semaphore_timedwait_trap + 10

1   libdispatch.dylib             0x00007fff5314d8ea _dispatch_sema4_timedwait + 72

2   libdispatch.dylib             0x00007fff53142dcb _dispatch_group_wait_slow + 97

3   com.apple.photo.PAImaging     0x00007fff49470e71 -[PAPreviewMaker _renderVersionToSize:description:canceler:failureCode:] + 932

4   com.apple.photo.PAImaging     0x00007fff49472b57 -[PAPreviewMaker makePreviewForImageStyle:inputImage:orientation:outputSize:doRender:largePrevie wIsEmbedded:addMetadata:canceler:completion:] + 449

5   com.apple.photo.PAImaging     0x00007fff494339b0 -[PAPreviewWriter _imageForImageStyle:version:imageProxyState:inputImage:inputImageSize:descripti on:render:largePreviewIsEmbedded:canceler:previewMaker:] + 2532

6   com.apple.photo.PAImaging     0x00007fff49435924 -[PAPreviewWriter _inputImageForPreviews:imageProxyState:renderDescription:editStatus:force:outpu tImageStyle:canceler:previewMaker:] + 1446

7   com.apple.photo.PAImaging     0x00007fff49438a18 -[PAPreviewWriter _renderPreviewForImageVersion:imageProxyState:force:priority:canceler:] + 1426

8   com.apple.photo.PAImaging     0x00007fff4943d120 __70-[PAPreviewWriter renderThumbnailsForVersion:force:canceler:priority:]_block_invoke + 4353

9   libdispatch.dylib             0x00007fff53153e03 _dispatch_block_async_invoke2 + 102

10  libdispatch.dylib             0x00007fff5313dd50 _dispatch_client_callout + 8

11  libdispatch.dylib             0x00007fff5315220c _dispatch_queue_serial_drain + 635

12  libdispatch.dylib             0x00007fff531450fd _dispatch_queue_invoke + 373

13  libdispatch.dylib             0x00007fff53152f02 _dispatch_root_queue_drain_deferred_wlh + 332

14  libdispatch.dylib             0x00007fff53156d16 _dispatch_workloop_worker_thread + 880

15  libsystem_pthread.dylib       0x00007fff53402033 _pthread_wqthread + 980

16  libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 3:

0   libsystem_kernel.dylib         0x00007fff532c7562 __workq_kernreturn + 10

1   libsystem_pthread.dylib       0x00007fff5340226f _pthread_wqthread + 1552

2   libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 4:

0   libsystem_kernel.dylib         0x00007fff532c7562 __workq_kernreturn + 10

1   libsystem_pthread.dylib       0x00007fff5340206a _pthread_wqthread + 1035

2   libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 5:: com.apple.NSEventThread

0   libsystem_kernel.dylib         0x00007fff532bd7c2 mach_msg_trap + 10

1   libsystem_kernel.dylib         0x00007fff532bccdc mach_msg + 60

2   com.apple.CoreFoundation       0x00007fff2b928355 __CFRunLoopServiceMachPort + 341

3   com.apple.CoreFoundation       0x00007fff2b9276a7 __CFRunLoopRun + 1783

4   com.apple.CoreFoundation       0x00007fff2b926d23 CFRunLoopRunSpecific + 483

5   com.apple.AppKit               0x00007fff290473c8 _NSEventThread + 184

6   libsystem_pthread.dylib       0x00007fff534026c1 _pthread_ + 340

7   libsystem_pthread.dylib       0x00007fff5340256d _pthread_start + 377

8   libsystem_pthread.dylib       0x00007fff53401c5d thread_start + 13

Thread 6:

0   libsystem_kernel.dylib         0x00007fff532c7562 __workq_kernreturn + 10

1   libsystem_pthread.dylib       0x00007fff5340226f _pthread_wqthread + 1552

2   libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 7:

0   libsystem_kernel.dylib         0x00007fff532c7562 __workq_kernreturn + 10

1   libsystem_pthread.dylib       0x00007fff5340226f _pthread_wqthread + 1552

2   libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 8:

0   libsystem_kernel.dylib         0x00007fff532c7562 __workq_kernreturn + 10

1   libsystem_pthread.dylib       0x00007fff5340226f _pthread_wqthread + 1552

2   libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 9:: Dispatch queue: Low Priority BIP

0   libsystem_kernel.dylib         0x00007fff532bd7fe semaphore_wait_trap + 10

1   libdispatch.dylib             0x00007fff5314d82e _dispatch_sema4_wait + 16

2   libdispatch.dylib             0x00007fff53145911 _dispatch_semaphore_wait_slow + 101

3   com.apple.photo.PAImaging     0x00007fff4943be07 -[PAPreviewWriter renderThumbnailsForVersion:force:canceler:priority:] + 622

4   com.apple.photo.PAImagingCore 0x00007fff4959dc09 -[PAPreviewWriterService renderThumbnailsForVersion:force:canceler:priority:] + 96

5   com.apple.photo.PAImagingCore 0x00007fff495fb39c -[RKBackgroundImageProcessor performJob:context:] + 978

6   com.apple.PhotoFoundation     0x00007fff49675180 __72-[PFWorkContext(BackgroundServiceManager) dispatchPerformJob:withReply:]_block_invoke.196 + 73

7   libdispatch.dylib             0x00007fff53145591 _dispatch_call_block_and_release + 12

8   libdispatch.dylib             0x00007fff5313dd50 _dispatch_client_callout + 8

9   libdispatch.dylib             0x00007fff5315220c _dispatch_queue_serial_drain + 635

10  libdispatch.dylib             0x00007fff531450fd _dispatch_queue_invoke + 373

11  libdispatch.dylib             0x00007fff53152f02 _dispatch_root_queue_drain_deferred_wlh + 332

12  libdispatch.dylib             0x00007fff53156d16 _dispatch_workloop_worker_thread + 880

13  libsystem_pthread.dylib       0x00007fff53402033 _pthread_wqthread + 980

14  libsystem_pthread.dylib       0x00007fff53401c4d start_wqthread + 13

Thread 10 Crashed:: Dispatch queue: GL0.low.run

0   libsystem_malloc.dylib         0x00007fff5331f269 szone_malloc_should_clear + 12

1   libsystem_malloc.dylib         0x00007fff53320cc0 malloc_zone_calloc + 87

2   libsystem_malloc.dylib         0x00007fff533215d6 calloc + 30

3   com.apple.CoreImage           0x00007fff2c48a975 CI::ProgramNode::build_program_graph(CI::Node*, CI::Context*, CI::NodeToNodeMap&, bool) + 133

4   com.apple.CoreImage           0x00007fff2c3bbd29 CI::Node::program_graph(CI::Context*, CI::NodeToNodeMap&, bool) + 63

5   com.apple.CoreImage           0x00007fff2c48b20d invocation function for block in CI::ProgramNode::build_program_graph(CI::Node*, CI::Context*, CI::NodeToNodeMap&, bool) + 762

6   com.apple.CoreImage           0x00007fff2c4394f8 CI::GraphObject::traverse_preorder_stoppable(CI::GraphObject*, CI::GraphObject*, int, int, bool (CI::GraphObject*, CI::GraphObject*, int, int) block_pointer) + 52

7   com.apple.CoreImage           0x00007fff2c439532 CI::GraphObject::traverse_preorder_stoppable(CI::GraphObject*, CI::GraphObject*, int, int, bool (CI::GraphObject*, CI::GraphObject*, int, int) block_pointer) + 110

8   com.apple.CoreImage           0x00007fff2c48ab39 CI::ProgramNode::build_program_graph(CI::Node*, CI::Context*, CI::NodeToNodeMap&, bool) + 585

9   com.apple.CoreImage           0x00007fff2c3bbd29 CI::Node::program_graph(CI::Context*, CI::NodeToNodeMap&, bool) + 63

10  com.apple.CoreImage           0x00007fff2c4bcf38 CI::NoopNode::program_graph(CI::Context*, CI::NodeToNodeMap&, bool) + 68

11  com.apple.CoreImage           0x00007fff2c48b20d invocation function for block in CI::ProgramNode::build_program_graph(CI::Node*, CI::Context*, CI::NodeToNodeMap&, bool) + 762

12  com.apple.CoreImage           0x00007fff2c4394f8 CI::GraphObject::traverse_preorder_stoppable(CI::GraphObject*, CI::GraphObject*, int, int, bool (CI::GraphObject*, CI::GraphObject*, int, int) block_pointer) + 52

13  com.apple.CoreImage           0x00007fff2c439532 CI::GraphObject::traverse_preorder_stoppable(CI::GraphObject*, CI::GraphObject*, int, int, bool (CI::GraphObject*, CI::GraphObject*, int, int) block_pointer) + 110

14  com.apple.CoreImage           0x00007fff2c48ab39 CI::ProgramNode::build_program_graph(CI::Node*, CI::Context*, CI::NodeToNodeMap&, bool) + 585

15  com.apple.CoreImage           0x00007fff2c3bbd29 CI::Node::program_graph(CI::Context*, CI::NodeToNodeMap&, bool) + 63

16  com.apple.CoreImage           0x00007fff2c4bcf38 CI::NoopNode::program_graph(CI::Context*, CI::NodeToNodeMap&, bool) + 68

17  com.apple.CoreImage           0x00007fff2c48b20d invocation function for block in

Downgrading a device's iOS version isn't supported.

If you erase and reinstall it will just be system that reinstalls and you'll need to migrate from your backup disk.

However that step would be a good test of the disk because it will be a clean Mac OS. Then if that works you could migrate back:

How to move your content to a new Mac - Apple Support

If you replace the drive, and clone it will be an identical copy of your present system and will have everything you need, including all of your data and programs.

riverdancer9 wrote:

 

I chose to reinstall.  Ok so far?

It should be OK.

Which OS are running now?

If you do not have a Recovery Partition, do you have the DVDs the Mac shipped with the Mac? If you do you can use Install Disc 1to wipe the drive and install the original system. Then upgrade from there.

Startup – Computer restarts by itself – Yosemite

Startup Issues - Resolve

Startup Issues - Resolve (2)

Startup Issues - Resolve (3)

What does Wireless Diagnostics show?

Wireless Diagnostics

Wi-FI connection drops

Wi-Fi Problems in OS X Yosemite

Wi-Fi Problems in OS X Yosemite (2)

Wi-Fi Problems in OS X Yosemite (3)

WiFi Potential Temporary fix - Yosemite

Also try turning off Bluetooth.

If your Wi-Fi source is capable of generating a 5 GHz Wi-Fi network, try that to help avoid conflicts with Bluetooth.

No.

You're welcome.

No, Nothing will be removed if you don't erase your drive first. Make sure you have a good backup before you reinstall or upgrade.