Comment 13 for bug 1810176

I have the same problem on Linux Mint 18.3 (Ubuntu derivitive). I could access files and folders except for the folder containing a whole lot of images. Error message was:

The folder contents could not be displayed.
Sorry, could not display all the contents of "Wallpaper" : libmtp error: could not get object handles.

I tried restarting the computer, and the phone independently - neither resolved the issue. After researching this issue, several people suggested that the number of files (in the folder) may be an issue.

This work-around resolved the issue for me: On my phone, I created a new folder at the same level as the problem folder, and moved 1 file from the problem folder to the new folder. I could then access the problem folder from my Linux machine. I copied some more files into the folder, and then moved the relocated file back into the previously problematic folder and could still access the folder. I then removed the newly created (and now empty) folder.

Ok. Some more information that may help resolve the problem:
There were 1788 files in the folder when I encountered the issue.
There were 1787 files in it after I moved 1 file and could access the folder.
There were 1816 files in the folder when I'd finished copying files (and it was still accessible).
The folder containing the files is a sub folder of another user created folder on the phone.

The libmtp components on my system are:
$ dpkg -l | grep libmtp
ii libmtp-common 1.1.10-2ubuntu1 all Media Transfer Protocol (MTP) common files
ii libmtp-dbg:amd64 1.1.10-2ubuntu1 amd64 Media Transfer Protocol (MTP) debugging symbols
ii libmtp-dev:amd64 1.1.10-2ubuntu1 amd64 Media Transfer Protocol (MTP) development files
ii libmtp-doc 1.1.10-2ubuntu1 all Media Transfer Protocol (MTP) library documentation
ii libmtp-runtime 1.1.10-2ubuntu1 amd64 Media Transfer Protocol (MTP) runtime tools
ii libmtp9:amd64 1.1.10-2ubuntu1 amd64 Media Transfer Protocol (MTP) library
ii libmtpserver-dev 0.0.4+15.04.20150219-0ubuntu3~gcc5.1 amd64 Library for implementing MTP protocol servers - development files
ii libmtpserver1 0.0.4+15.04.20150219-0ubuntu3~gcc5.1 amd64 Library for implementing MTP protocol servers - shared library

Other information that may help (though I suspect that this problem is not specific to this):
$ inxi -MSf
System: Host: pj1 Kernel: 4.15.0-106-generic x86_64 (64 bit) Desktop: Cinnamon 3.6.7
           Distro: Linux Mint 18.3 Sylvia
Machine: System: Gigabyte product: B250M-D3H v: Default string
           Mobo: Gigabyte model: B250M-D3H-CF v: x.x Bios: American Megatrends v: F2 date: 11/25/2016
CPU: Quad core Intel Core i5-7400 (-MCP-) cache: 6144 KB
           clock speeds: max: 3500 MHz 1: 974 MHz 2: 2984 MHz 3: 2485 MHz 4: 2992 MHz
           CPU Flags: 3dnowprefetch abm acpi adx aes aperfmperf apic arat arch_perfmon art avx avx2 bmi1 bmi2 bts
           clflush clflushopt cmov constant_tsc cpuid cpuid_fault cx16 cx8 de ds_cpl dtes64 dtherm dts ept erms
           est f16c flexpriority flush_l1d fma fpu fsgsbase fxsr ht hwp hwp_act_window hwp_epp hwp_notify ibpb
           ibrs ida intel_pt invpcid invpcid_single lahf_lm lm mca mce md_clear mmx monitor movbe mpx msr mtrr
           nonstop_tsc nopl nx pae pat pbe pcid pclmulqdq pdcm pdpe1gb pebs pge pln pni popcnt pse pse36 pti pts
           rdrand rdseed rdtscp rep_good sdbg sep smap smep ss ssbd sse sse2 sse4_1 sse4_2 ssse3 stibp syscall tm
           tm2 tpr_shadow tsc tsc_adjust tsc_deadline_timer vme vmx vnmi vpid x2apic xgetbv1 xsave xsavec
           xsaveopt xsaves xtopology xtpr

Seems that this is an ongoing issue, so I hope this information helps to resolve the issue in the end.